Switching to an N95 mask gives a 75x boost in Covid protection | Hacker News Reader

Switching to an N95 mask gives a 75x boost in Covid protection

axios.com

288 pointsdaveaiello478 comments

Notably the paper that they refer to does not actually count infections it is all about meta analysis, and simulation and particle size etc

No actual controlled evaluation that measured protection against the actual infection has ever found effect remotely as strong as claimed here - and sometimes the opposite is found.

Yes, mask may work in some circumstances, but everyone wearing them all the time in social settings? The issue is far from settled.

As an example Austria has mandated N95 masks since Summer, people, store clerks take it seriously and actually enforce them. Been there myself and seen/experienced that myself.

Is Austria on a different track when it comes to the epidemic? Not really. Where is the 75x protection?

Why isn’t there more protection shown? Is it people not wearing the masks well? Or not wearing them consistently?

One thing I’ve thought was ludicrous since the beginning of the pandemic was the idea that you should mask in a restaurant “except while eating.” That’s comically stupid. I understand we love our restaurants and don’t want them all going out of business (and that huge workforce being unemployed!), but there’s no point fooling yourself, if you aren’t going to wear the mask the whole time when you go somewhere then there’s really no point.

But risk isn't a 1/0 binary. Every moment you are wearing a mask changes your risk. Spending 1 hour in a restaurant vs 10 hours in a restaurant. It all adds up and it all matters.

So yeah, taking your mask off while you eat is definitely going to raise your risk. But not as much as simply not wearing a mask the entire time you're in a restaurant, moving around, getting closer to people and different areas of the restaurant, which probably all have variable particles in the air, etc.

Risk isn't binary. But constantly taking your mask on and off has risks of its own from touching and rubbing. Similar to not touching your face with your hands to avoid germs, you should not be touching your mask frequently.

> So yeah, taking your mask off while you eat is definitely going to raise your risk.

I don’t think that’s usually how it works. A regular mask is good at “curbing the fanout” so to speak, but not so great at filtering incoming air. Taking your mask off while you eat is going to raise the risk for everybody around you—unless you use an N95 mask or similar equipment (and use it properly), what your mask does is mostly in fact protecting bystanders from asymptomatic COVID that you may have acquired by restricting outgoing airflow and virions within.

Now consider real life, where not everyone wears masks, and my guess is depending on where you are easily less than 10% of mask-wearers wear masks properly. They don’t wear masks over their nose, leave huge gaps between the mask and their face, take off their mask to sneeze or cough (I kid you not). They try to make it easier to breathe, and by extension defeat the point of wearing a mask.

Unsurprisingly, masks is the easiest and cheapest measure to be taken, compared to e.g. auditing and upgrading air circulation infrastructure.

Unsurprisingly, in many cultures people who think that the mask protects them and don’t know about asymptomatic COVID choose not to wear a mask because they bravely don’t care if they get sick.

Unsurprisingly, for the rest of us there’s very little point in being the one-in-ten person wearing a mask in what is a fluid exchange fest anyway.

Unsurprisingly, as a result people tend to not wear masks if they can get away with it, and restaurant owners and other people in charge of enforcing the measure on their territory would instruct staff to let things slip rather than alienate their patrons over a seemingly useless measure.

Meanwhile, masks are not free. Both in terms of money, and in terms of wellbeing. A properly worn mask necessarily obstructs breathing. One risks becoming infected by their own mask which accumulates virions in circulation (and if you do rotate your mask, an argument could be made that reduced exposure to viruses long-term may weaken the immune system—though I’m not sure if there were studies to support or refute that).

Nevertheless, a measure has been taken, and local policymakers may now rest with a false sense of security.

>A regular mask is good at “curbing the fanout” so to speak, but not so great at filtering incoming air.

That applies for cloth masks and alike. N95/PFF2 is a protective gear and should filter ~95% of particles where N99/PFF3 is ~99% if given a perfect fit. Beards and other stuff can reduce the efficiency to ~30% though.

> Meanwhile, masks are not free.

But they are not expensive and can be rotated.

> A properly worn mask necessarily obstructs breathing.

Only if you already have difficulty breathing. Studies show no impact on blood oxygenation whatsoever due to the usage of masks in normal situations. What they cause is discomfort due to retention of breath humidity and heat. It sucks to wear a PFF3 while doing intensive exercise,

> One risks becoming infected by their own mask which accumulates virions in circulation.

Any viruses that accumulate on a mask you would be breathing otherwise.

> ...reduced exposure to viruses long-term may weaken the immune system—though.

That makes sense. The nose epithelial cells are the 1st line of defense against airborne pathogens. By reducing our exposure we are reducing the efficiency of those cells.

> Now consider real life, where not everyone wears masks, and my guess is depending on where you are easily less than 10% of mask-wearers wear masks properly. They don’t wear masks over their nose, leave huge gaps between the mask and their face, take off their mask to sneeze or cough (I kid you not). They try to make it easier to breathe, and by extension defeat the point of wearing a mask.

True. Where I live masks are not enforced, we are in the summer and >90% of those I see are not using it. But the few that are still using it are doing it properly.

> Nevertheless, a measure has been taken, and local policymakers may now rest with a false sense of security.

I agree with you but not because I don't think masks work. It's just that people think that now that they have took the jab and put the mask they can do whatever they want including staying for hours in a fully occupied and closed room where a guy is coughing non-stop. It's just that people are stupid and irresponsible.

When I studied workplace safety and health we learned that protective gear is the last measure you adopt. If you have place where exists a risk of people falling you first should attempt to eliminate the risk and improve the ergonomics of the place, like installing guardrails. If that isn't possible you enact administrative policies like forbidding from transiting in the dangerous place unless they have authorization and a reason to be there. And only then you provide protective gear for those.

> That applies for cloth masks and alike

Yes. Yet (I know that the article is about N95 specifically, but in general) that is the majority of masks worn. I haven’t been to a country where N95 masks were freely distributed, are there any?

> But they are not expensive and can be rotated.

In my experience, depending on where you are in the world, N95 masks can be quite expensive and/or very difficult to come by. Rotating them is definitely infeasible for many people.

> Any viruses that accumulate on a mask you would be breathing otherwise

I disagree on this, because the potentially virion-containing matter is 1) accumulating, and doing so 2) next to the entrance to your breathing pathways (given the mask is worn properly). It’s not a binary thing where you inhale a single virus and get sick, repeat exposure and concentration play a role in how large will your dose be and whether you become infected.

> I agree with you but not because I don't think masks work.

Don’t get me wrong, I think masks can work, I just think making them work the way they work in theory is much more effort than anyone would be willing to invest (the amount of effort also depending on social norms in a given country), and policymakers should be acutely aware that requiring masks will not in practice yield the benefit they may expect based on how masks are shown to perform in lab tests, and plan accordingly.

> When I studied workplace safety and health we learned that protective gear is the last measure you adopt.

This is an interesting point!

> A properly worn mask necessarily obstructs breathing.

I’m really not sure why people keep claiming this, as if a lot of us haven’t been wearing a variety of masks for years at this point.

If wearing a mask doesn’t make it noticeably more difficult to breathe, most likely you have air bypassing the mask—look for gaps and try to get a better fit.

My KN95s put visible lines on my face the day after and make my ears hurt like hell. They're sealed, and I can tell I'm breathing through one. But "difficult", nah.

Then we’re on the same page. It’s necessarily comparatively more difficult to breathe with than without, that’s how you can tell you’re breathing through a filter. (The absolute degree of difficulty depends on the individual and preexisting conditions.)

> an argument could be made that reduced exposure to viruses long-term may weaken the immune system—though I’m not sure if there were studies to support or refute that).

My mental model of the immune system would say this isn't how it works but I am not an expert:

Immune response is very specific which means that if you have been exposed to 10 different 'sorts' of viruses then your immune system has likely learned a specific response to those specific viruses. If you now become affected with an 11th kind, then your immune system cannot reuse the specific response it has already learned but has to learn to fight a new enemy.

Thus there is very little benefit of becoming infected with a particular virus if you can avoid it.

The implications are that by wearing masks or isolating you are avoiding getting viruses which are currently in circulation and if you stop wearing masks or stop isolating then you will likely catch up with the viruses currently in circulation (so you are sick more often), but the individual infection isn't more severe because you haven't had to deal with a lot of viruses for some time.

“Weaken the immune system” not like with muscles from lack of physical exertion, but like with an antivirus database that stops receiving signatures from the ongoing evolution of viruses around.

My mental model (would not mind if it is wrong) suggests that the number of distinct viruses in our environments is surprisingly high (I do not think we have identified all of them yet), and it is thanks to continued repeat exposure (re-training immune system to mutations, etc.) throughout our daily life that we do not get constantly sick.

Not to say I think it would be disastrous for a person to stop wearing a mask after a while of wearing mask properly—one would just be ill for a bit, like you say. Although I would presume combining multiple infections at the same time could make it a little less pleasant.

Over the long term your risk of exposure approaches 1 regardless of whether you wear a mask in restaurants.

https://www.medpagetoday.com/opinion/vinay-prasad/94646

I don't know (and I'm not defending this validation, as I take issue with a number of premises) but my understanding of the justification is that restaurants can relatively easily space out/put dividers up between their tables (such that risk of transmission between parties at different tables is lower), but that no such accommodation can be made easily for the aisles, bathrooms, bar, and other intermediate spaces. Thus the rule, which around here is "wear a mask if you aren't seated at your table".

Given how restaurants around here are still packing people in, though, one has to assume that the initial table-spacing premise is compromised, undermining the whole endeavor.

The dividers are pretty silly if the virus is as airborne as is now believed.

They are. But limiting the number of people you’ve been potentially exposed to to just the people directly next to you is obviously safer than being exposed to every person between your table and the bathroom/exit.

If it's airborne, you're exposed to all of the people in the facility, and all of the people in it within the last few hours. The dividers likely make minimal if any difference.

sigh I didn’t say that the dividers help. I in fact explicitly agreed with you that they’re useless.

That being said, the virus isn’t magically going to fill the entire space equally from one infected person. There is a distance factor involved, and the closer you are unmasked the higher your risk. So only unmasking at your table cuts your risk pool down to the tables immediately proximate to you, rather than everyone you walked by, and anyone you shared the bathroom with. It’s not as safe as staying home, but it’s better than being unmasked the entire time.

Oh, and the risk isn’t going to hang around hours after the fact, unless if you’re in a completely unventilated space. Commercial restaurants change their air over a recommended 8 times an hour.

1. Air turnover is not the same as changeover. Turnover is only relevant if viral filtration is in place, which it generally isn't. Changeover is outside air, and for energy conservation, very little outside air is generally mixed in. (Some spaces do either or both of these. Airplanes provide an example of better filtration than usual, cruise ships are an example of more outside air than most buildings, and you can draw your own conclusions between those examples.)

2. Research shows takes less time to diffuse than you'd think, and lingers longer than you think. Since spring 2020 research has shown to wait till tomorrow if someone infected was in the space today.

3. Your own mask mitigates this, as does the amount of time you're breathing the infected space, as does the amount of human turnover (how many rolls of the dice of the space hosting an infected breather, and how long are they exhaling in the space).

> 2. Research shows takes less time to diffuse than you'd think, and lingers longer than you think. Since spring 2020 research has shown to wait till tomorrow if someone infected was in the space today.

Do you have a citation for this? I would be interested in reading this study.

1. The recommendation is 6-8 changes of outdoor air per hour. See ASHRAE 62.1. For comparison personal homes are recommended to change over their air 0.35 times per hour.

2. I would like to see that cross referenced against ventilation capacity. Again, restaurants are supposed to be changing their air over with outside air a lot, the idea that a properly ventilated space would have represent an infection risk days later is in the “doubt” category for me. Basically, please provide a source.

Heck, last time I was in Vegas I could barely smell people smoking a few feet away from me, the ventilation was that good. If cigarette smoke is the metaphor we’re going with for viral particles and dividers, that strongly implies that better ventilation yields a lower infection risk.

3. Exactly. This is an argument for masking when you’re not eating. It’s not 0 risk, but it’s lower. How much lower is debatable, and obviously depends on more circumstances than just masking policy alone.

Personally I’d rather just get takeout when local case loads are high, like right now.

The dividers, insofar as they impede overall airflow, might make things worse. Would like to know whether there's a study on that.

> my understanding of the justification is that restaurants can relatively easily space out/put dividers up between their tables (such that risk of transmission between parties at different tables is lower)

Because air doesn't move? It doesn't mix? On the contrary, the virus persists in the air for longer than an entire room air turnover.

Since Feb 2020, the studies show HVAC's air patterns in restaurants do infect other tables, quickly even. Roughly, air handling collects contaminated air and spews it on some tables in concentrated form (those tables experience all the air fast, not just subset of diffuse air more slowly; then in time all the air is mixed). Similar findings in 2021 for classrooms where student desks at risk are heat mappable based on HVAC configurations.

Grandparent post is right. You see other polls saying e.g. 60% of people being extra careful now with Omicron, at the same time, nearly 60% still going out to eat. So either people are stupid, or just don't understand because nobody's informing them. I'd suggest your post falls in the under-informed category: dividers are for how droplets work, but not for how air works.

Ridiculous we still don't deal with the air situation, but (a) way too much narrative was set back in the "it's not airborne" days for the media or masses to be interested in grappling, and (b) no landlord wants* to fix the air handling which was all sized for energy cost reduction not health.

* On HVAC upgrades, it's initially interesting that HVAC firms aren't upselling HEPA filtration etc. -- why isn't capitalism solving this problem? Surely they're lobbying for the new business! But then one remembers that 'venue shopping' or 'advice shopping' is a thing. Any HVAC firm under contract to workplace building owners is putting the relationship at risk if they tell the landlord or occupants on the record to spend a bunch of extra money. On the contrary, their incentive to keep the building contract is aligned with the landlord's incentive to not hear about having to spend 10x the original cost of the system on upgrading it.

Only an anecdote, but I recently visited a restaurant that prominently advertised they had installed a high end air filtration system, and it did smell kind of “filtered” inside (don’t know how to describe the smell but hopefully you know what I mean).

Perhaps the market will eventually move this way, and it just takes time? Certainly it is expensive so I don’t think the market will move this way unless consumers demonstrate they care and preferentially visit places with fancy HVAC.

It could be Ozone. Possibly harmful for human depending on concentration but sometimes used for human.

EPA says that just HEPA filter is enough to catch covid, so it seems that there are less chance to upsell filter only. Selling more appliances would be good. https://www.epa.gov/coronavirus/air-cleaners-hvac-filters-an...

Standing in a crowded waiting area is ≠ sitting at a spaced out table maybe with a divider between you and the other tables.

The particles are floating around in the air. They don’t hit the glass and turn around and go home, they continue to float and a draft or whatever will disperse the particles throughout the room.

Who gets to decide what size interior is ok? Or what crowded is?

It’s all arbitrary and you all fell for it.

Just let omicron spread, accept it’s another seasonal flu, and move the fuck on.

To be fair, I wasn't referring to my own personal risk tolerance but I guess trying to explain a seemingly arbitrary rule... I haven't eaten at a sit down for the last two years because I have small children and expecting them to follow any sort of strict masking protocol is unrealistic.

I also have multiple close family members who work in ICU and healthcare and I really don't think you want Omicron to spread faster than it needs to... That's an extremely shallow selfish mindset.

Edit: Just wanted to share an article from yesterday on the state of hospitals. I have friends/family that are super badass just like you, until they get in a car accident and need a bed at the ER. All the sudden shit gets a little more real and personal... https://www.npr.org/sections/health-shots/2022/01/11/1071568...

Here's a good infographic from a country with a seemingly better public information response. It talks about both droplets and aerosols. Simply put: dividers don't help much with aerosols, or may concentrate the particles from multiple users of the same space.

http://aerosol.nsysu.edu.tw/en/scopes/108

I’ve never really understood why people are confused by the eating thing. The point is obviously harm reduction, not harm elimination. If you’re going to eat out, it’s obviously better to not get exposed to every single person you walked by when you’re not doing an activity that’s impossible with a mask on. This has always been extremely obvious to me, and a natural consequence of trying to keep restaurants open and case loads down.

Now at various points I’ve wondered why restaurants were open, but that’s a different discussion.

>The point is obviously harm reduction, not harm elimination.

Or the point is theater.

If you're going to have indoor dining--and most places have made that decision--people can't wear masks when they're eating and drinking. And the relatively small number of times I've been eating inside it's pretty obvious that wearing a mask between the door and your table almost certainly makes a negligible difference in risk.

I’ve always assumed the virus can enter the body through the eyes, who’s tear ducts lead to the nasal passages.

Yes. Some physicians I know now wear goggles, or glasses with foam fittings kind of like swim goggles.

It's an effective way to continue to collect tax revenue while maintaining the illusion of control. Don't point it out or it will spawn a series of conversations where people endlessly divide and multiply statistically negligible percentages.

Could it be something as simple as ignoring that we're all touching our masks, our clothing, our eyes. Basically, did we optimize one part of the problem while ignoring all others and the net effect is basically zero?

This is so annoying. They measure X and then claim that effect is Y. Which was not measured at all.

Austria requires FFP2 which is not quite as strict of a standard as NIOSH N95. At the 95+% filtering rate, it’s really the mask’s fit that is making or breaking filtering ability.

N95 masks fit very tightly, come in different shapes and sizes to fit different people, and will leave imprint marks on a persons face. This is beyond what the general public is really willing to go through, so they’re really not used many places outside of medical settings, and it’s not really realistic to have them properly fit tested by the general public.

We do have real world data to show that properly fit tested N95s work very well when used by trained people, from the hospital settings in which this is done. But like any equipment, it’s only as good as it is used properly.

It may very well be possible that leaking FFP2 masks aren’t much different than other masks in effectiveness against highly transmissible variants.

I wear N95, but... I have a beard. I'm painfully aware I'm sabotaging my own efforts and do not have a perfect seal.

I’m amazed at the number of people I see wearing N95s or KN95s with a clear gap at the top. Why bother?

I have a collection of various 94+% masks that I amassed towards the beginning of the pandemic. About 6 or 7 types. Only 1 of them doesn’t fog my glasses in the winter (and it’s a freakin Honeywell respirator) That means all of the others are leaking, even when I wear them “properly”

Water vapor is a lot smaller than viral particles and is likely to pass through even a N95 mask, which is good, as you'd drown pretty quickly if it didn't.

I wouldn't read too much into fogging.

(That said, I do wish there were better options for people with giant noses like mine.)

I mean, they’re fogging because the top of the mask leaks, and the breath takes the path of least resistance and goes around rather than out of the mask.

Yup, exactly. I use my glasses to seal the top. It's weird but it works.

Likely, but not necessarily. My silicone half-face (with disabled check valves) slightly fogs my glasses because enough water vapor is leaving the filter close to my glasses. I'm sure it's not leaking, because I can feel the silicone pull away from my face when it does.

For me, fogging my glasses means I have a leak and the air is being forced out gaps around my nose. Maybe under extreme weather conditions a perfect fit would still fog, but that's not what the op is talking about.

I think it's more about the direction of the water vapor than the fact that the masks can pass vapor. If there was no leakage one might expect vapor to leave through the mask uniformly or in the same pattern as it did without masking (e.g. mostly forward.)

I used to shave and use medical tape to seal KN95 masks around my nose. Since the vaccine came out, I don't bother anymore.

By my own very much baseless estimation of people wearing FFP2 in Germany: about 10% have their noses out, 60% have the mask completely unfitted, and 30% have at least tried to fit it.

> I’m amazed at the number of people I see wearing N95s or KN95s with a clear gap at the top. Why bother?

Uncharitably: People think it's a magical talisman; wear this mask and be protected. There's no grasp of the mechanism, so "wearing" the mask can be arbitrary.

Charitably: If people grasp how masks work, it's easy to forget, or not think of it, or not check that it's (still) on correctly.

(Bluntly, I think the former option more likely, but I try to think of charitable options)

I have a KN95. I can't get it to fit on the top. Always fogs my glasses. But when I breathe in, I can clearly see by the fabric's motion that air is substantially being pulled through the material rather than around it (edit: or that might just be pressure differential).

In any case, we are talking about mitigation of risk, minimization of exposure. If my mask is only filtering 80% of the air at 95%, that still a lot fewer viral particles I'm exposing myself to than otherwise. I don't think that its a matter of whether 1 viral particle gets through, but how many that determines likelihood of an infection or serious illness.

And its effectiveness is backed up by studies of unfitted 95s.

Depends on degree; I was thinking of people who aren't even covering their noses when I wrote my comment. Good point, though; I hadn't thought of "physically doesn't fit".

> I have a KN95. I can't get it to fit on the top. Always fogs my glasses. But when I breathe in, I can clearly see by the fabric's motion that air is substantially being pulled through the material rather than around it.

IIRC, KN95s were designed for flatter, asian noses. I think I read somewhere that one of the motivating factors for the design was that it's harder for asians to get a good fit with some types of N95, because they were designed for caucasian noses.

I have a big nose, so KN95s never work for me, unless I retrofit a really long and beefy metal strip for the nose.

> I can clearly see by the fabric's motion that air is substantially being pulled through the material rather than around it.

I suspect that the fabric’s motion doesn’t mean what you think. You’re just seeing motion from the pressure change. A non permeable plastic film will also move as the pressure changes. This doesn’t mean any air is going through it.

> If my mask is only filtering 80% of the air

If your mask is leaking around the edges, it is extremely unlikely that your mask is filtering anything close to 80% of the air.

You might be right about that.

My most important point though is that if your goal is to reduce your risk, then wearing an 95 type mask, even an unfitted one, achieves that goal. Its not all or nothing.

On the bright side, if you are vaccinated and reasonably healthy, the risk from COVID is quite low. I’m still wearing cloth masks.

Lately, I've been using FFP3 masks with N95-style double headbands. All the FFP3 masks I've seen have a foam nose bridge that makes it much easier to get a good seal than any of the KN95s I've seen.

FFP3 is a higher standard anyway, ~equivalent to the US's N99.

Interestingly, fog on glasses does not appear to be a strong indicator of a poor fit: https://www.ijccm.org/doi/IJCCM/pdf/10.5005/jp-journals-1007...

Consider how the fit can be pretty and still result in fogging up your glasses. In general but especially on cold days, you avoid fogging your glasses because the air you exhale is moving usually quickly enough that it is past your glasses by the time any of it starts diffusing and moving upward.

An N95 slows it down enough that some of the warm, moist air will make its way up to your glasses. It'll be especially noticeable if you're outdoors int he winter. Plus, the shape of some N95s and KN95s looks like it would cause some of your exhaled air to diffuse out through the mask in a more upward direction that it would if you were maskless.

Interesting!

So two of what I considered indicators of fit are probably wrong. I'll call that a good day. (:

Those are mostly the people just wearing a mask because they have to. Personally my thinking is "the mask mandate is here for a reason, and if I have to wear a mask anyway, I might as well wear it so it actually protects me", but even I have "misadjusted" an FFP2 mask for better ventilation when sitting in a 90% empty train on a hot day...

There is simply no system for random joe to find masks that fit them.

Suppose you buy a mask and it doesn't fit, what do you do, but random ones untill uou find one that works? They have no categorisation, even if you find one, often you cant but it again as shops change their stock randomly.

Also sometimes you buy a FP2 mask and if turns out it's not https://www.pcgamer.com/razer-rows-back-after-zephyr-face-ma...

I’m not talking about “poor fit”. I’m talking about a significant visible gap. As in I could probably put my pinkie between the mask and their face. I see this a lot and while I understand fitting masks can be hard, this it’s hard to explain like that.

This is sometimes an “optical illusion”. Good masks have a metal sheet there that you can bend to fit your nose. However, when you bend it, the outer cloth of the sheet pocket will not follow the curves as tightly, if at all. It appears as if the wearer had not attempted to bend the metal sheet at all.

I’m not sure what this means. The use of an N95 or equivalent provides value only when rightly fitting. It sounds like you’re describing a mask that gaps no matter how it’s fitted.

A lot of the people I see like this seem to have bent the nose piece so tight that it’s actually lifting the top edge off their faces (because the nose cannot fit in the tiny space created). I’m not sure if they think the absurdly tight nose piece is sealing better or if they are intentionally doing this to make it more “breathable”.

No. I’m saying that you cannot look below the mask around the nose to see whether there are gaps. The outer cloth is not an accurate indicator.

The too-tight nose piece is probably because that’s how the masks are packaged.

> The outer cloth is not an accurate indicator.

Ah, I see what you mean. I’m pretty sure that I’m not seeing an illusion most of the time, because I’m not looking at the cloth. I’m looking at the very visible skin beneath the gap. But it makes sense that the outer layer of cloth could be misleading.

> The too-tight nose piece is probably because that’s how the masks are packaged.

You’re probably right. I normally see this on the center-folded masks. This would mean that people are just throwing on the mask without fitting rather than doing an astonishing bad job at attempting to fit, or intentionally fitting to create a space. That’s certainly more understandable.

Humans learn quickest through mimeses (imitation of what they see). That is why airplane flights start with a certain ritual demonstration.

Why bother? In order to avoid punishment in places with mask mandates.

Most places are not mandating N95-equivalent masks. Certainly they are not in Seattle, where I live.

Rumors are that CDC might start recommending them. Which means states will follow suit. Anything to make it seem like they're doing something.

It could certainly happen. I hope not. We’re gonna see a lot of wasted n95s if so. Few people know how to fit them and a whole lot of people have beards.

Here in Czechia they're mandatory in public buildings.

They're still more effective than a surgical mask, even with a gap.

Are they? If most air is coming around the edges I’d expect that whether the mask is woven cloth, surgical, n95, or solid plastic just doesn’t matter much.

I'd have thought it's pretty straightforwardly a case that effectiveness is capped at the percentage that comes through the material; so as long as some is, a better material will do a bit better. For sake of argument if you're getting 80% effectiveness from a perfect fit, that's 40% if 50% air comes around the sides, and better than an alternative that's 20% effective however well it fits. (All made-up round numbers.)

Is it possible that "worse" masks actually perform better in this case, because more air actually passes through the material instead of through gaps? Not advising to use flimsy masks of course, just wondering.

I’m not sure if it is or not. It’s something I’d actually like to understand.

I would imagine that if there’s a significant gap, most air would actually bypass the mask entirely. And “significant” here is still fairly small. I’m thinking you only need a cross section as large as your nostrils for most air to flow around the mask. And as you make the mask less breathable/more resistive, more air will bypass the mask.

But I don’t know how accurate my assumptions are.

I mean, sometimes people don't really care and they have to just adhere to the rules. (Some of those people have already had covid and the vaccines and are at such low risk of spreading it or catching it, the reduction in risk posed by the mask is negligible.) People in the trades, or with similar hobbies tend to have them lying around. Plenty of times I've just grabbed a used up N95 dust mask I had lying in the truck because I had to run to the hardware store really quick and I forgot my more comfortable mask.

More often, it's probably just a lack of training / reading the instructions on how to press-fit the nose bridge.

Then there's people like me with weird faces that fail fit tests no matter how careful with basically everything except the duck masks.

It's the nose peeking over that gets me.

I've worn an FFP3 throughout, don't see the point in cloth or surgical masks. (With my nose firmly inside...)

Indeed! I doubt there are studies on this, but I wouldn't be surprised if wearing an N95 with a full enough beard is equivalent to not wearing a mask at all, or to wearing a t-shirt cloth mask.

Whenever I'm about to be in a place with people, I try to remember to fully shave that morning, so there's not even a day or two's worth of stubble preventing an N95 seal around my nose and mouth.

There has been a study! It didn't cover beards longer than 10 mm, however. Short answer: not as good as an N95 without a beard, but better than cloth.

https://pubmed.ncbi.nlm.nih.gov/34006963/

There are studies about how beards limit mask effectiveness.

https://www.nature.com/articles/s41370-021-00337-1

I got rid of my beard before a big (vaxx and mask required) convention in DC last weekend, wore an N95 to the best of my ability, and tested negative (PCR) more than 24 hours after, and I am still feeling fine.

The difference between N95 and cloth masks is so big that we should just treat cloth masks as no masks.

There's some truth to that, but if we try to mandate N95 masks and no longer allow cloth masks, that'll destroy the mandate altogether. The majority will simply ignore it.

There are studies; ultimately, nothing with COVID is binary - it's levels of protection, and even with a beard there are a lot of "depends" based on the length of beard, fit of mask, and proper wearing.

I do find that one kind of KN95 fits great even with my beard (which is short - ~5mm). I trim next to the nose so I have a good fit there, and my side/bottom are short enough that for the most part mask seems to "dig through" the hair and contact skin, kinda like the Studded tires dig through snow to get to ice.

But again, I'm aware that my protection is lower than if I shaved. Personal risks assessments are personal, mine is that I work remotely, am on video calls 6+ hours a day, and shaved I look like a 12 years old :). Meanwhile I very rarely go out, and if I do go out for groceries biweekly or so, and not at all now during omicron, distance + mask + booster provide a reasonable protection.

When the pandemic started, I had several of my friends jokingly tell me that it was time for my beard to go if I wanted to get the full protection of an N95. I jokingly told them that if it was between me loosing my beard and getting covid, I was getting covid (in my 20's for context).

Granted not the smartest decision but given my risk factors and the fact that I've never not had a beard since I could grow one, so people would likely not even recognize me without one. And two years on I have yet to be infected so I'll count my blessings as a stoke my glorious beard.

You could try the Singh Thatta method – basically, using a yoga/pilates elastic band as a headwrap, against which the N95 forms a tighter seal. I've done it a few times in higher risk situations, and while I feel a bit silly with it, the fit does seem significant better.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7532752/

Still better than a surgical mask. Would be better if you dropped the beard but don't let that discourage you from moving in the right direction.

> Would be better if you dropped the beard

It's unbelievable what the pandemic has caused people to think it's acceptable to say.

Or how quick to take offence to fairly benign statements a certain type of person is.

You're misreading that comment. "Better" refers to how well the mask functions at blocking the virus, not to a moral judgment that beards are sinful.

I'm the grandparent poster it was directed to, and I see it as a perfectly acceptable and correct thing to say given the context; if you feel the need to get offended on my account by taking it out context, it's a free world! :)

FWIW, my perspective: In context, I have implicitly stated my goal of self-protection and even indicated my awareness that beard is counter-productive. Saying N95's effectiveness would be improved by dropping the beard is merely factual and restating what I already said. I certainly don't find it an "unbelievable" statement :)

What is the "right direction" for dealing with a virus to which everyone will eventually be exposed? Why are people so lacking in humility that they're sure they know what's right? What are the odds that you're wrong?

https://www.medpagetoday.com/opinion/vinay-prasad/94646

Your article doesn't contradict the parent. Delaying exposure is the right direction.

Not sure I follow your line of questioning. It's a known fact that hospitals are overloaded. Anything we can do to reduce that load is a good thing. Hospitals are understaffed and overworked.

Masks provide positive ROI. Wearing a mask is really not asking a lot.

Hospitals were frequently overloaded by other seasonal respiratory viruses before 2020 but they just dealt with it and mandates weren't imposed on the rest of society. What's different now? It seems many physicians have a different perspective.

https://youtu.be/GklHGYY8vN8

(Not the parent post, but the bearded grandparent poster :)

Even if we want to deny existence of universal right, or societal right, there's still a personal right direction.

First, my goals (which are mandatory for any discussion of correct/incorrect approach, whether on personal or societal/policy level, to be even remotely productive. We can't discuss "what path is right for society" without being explicit about our priorities, goals, assumptions!): For me primary goal is to protect those vulnerable in my life, including my newborn, my elderly parents, my immunocompromised nephew. On path to that, as well as from selfish perspective (I have Asthma/Bronchitis and my lungs are crap), my effective goal is avoid getting COVID for as long as possible, ideally forever; and minimize its impact as much as possible.

Once those personal goals are laid out, the correct approach / right direction is easier to discuss and navigate. Certainly, at the very least, working toward postponing infection has so far been a brilliant decision - even today, getting omicron while vaccinated is better than a year ago getting delta while not vaccinated. My personal extrapolation is that postponing it further is even better, both for myself and for society (most health systems being comprehensively overwhelmed currently; in Toronto, Canada entire hospitals are shutting down and so my mantra is "don't get sick right now", not just Covid).

If you believe you have meaningful contribution to my right direction given my goals, I'm all ears :). I don't believe lack of humility is at issue here but again, let me know if I'm mistaken :).

The linked study actually uses FFP2 masks, not N95. Here's a relevant part from the abstract regarding how an FFP2 performs:

> We find, for a typical SARS-CoV-2 viral load and infectious dose, that social distancing alone, even at 3.0 m between two speaking individuals, leads to an upper bound of 90% for risk of infection after a few minutes. If only the susceptible wears a face mask with infectious speaking at a distance of 1.5 m, the upper bound drops very significantly; that is, with a surgical mask, the upper bound reaches 90% after 30 min, and, with an FFP2 mask, it remains at about 20% even after 1 h. When both wear a surgical mask, while the infectious is speaking, the very conservative upper bound remains below 30% after 1 h, but, when both wear a well-fitting FFP2 mask, it is 0.4%.

Hmm. Thanks for pointing that out — that’s really bad reporting. These designations mean something.

FFP2 has more test then N95. [1] There are several shapes of FFP the one which is dominating in Austria (and Czechia and Slovakia) is not the only one.

[1]: https://www.wired.co.uk/article/what-are-n95-and-ffp2-face-m...

There are many shapes of all types of masks. Shape is important but only one part of proper fit.

Exactly. Two additions:

- N95's are used in many other industrial settings - medical is just where they're used to protect against covid. They're terrific masks when used appropriately.

- N95's do nothing to protect against getting covid through your eyes, which is a perfectly viable means of contracting SARS-CoV-2, as with any similar virus [1]. This makes the 75x reduction figure seem particularly silly.

(disclaimer, I make a mask with integrated eye protection)

[1] I cite some studies here: https://narwallmask.com/#h:why-is-eye-protection

> N95 masks fit very tightly, come in different shapes and sizes to fit different people, and will leave imprint marks on a persons face. This is beyond what the general public is really willing to go through, so they’re really not used many places outside of medical settings, and it’s not really realistic to have them properly fit tested by the general public.

That's not true. They're extremely common in construction for dealing with dust and paint aerosols. I wouldn't be surprise if that's the application they were actually developed for.

At the beginning of the pandemic, I had a bunch because I always use one when I sand or spraypaint.

You’re correct and I’m aware of their use in industry. I was unclear but what I meant was that they’re not commonly used by the general public for COVID protection outside of medical settings.

> You’re correct and I’m aware of their use in industry. I was unclear but what I meant was that they’re not commonly used by the general public for COVID protection outside of medical settings.

That's not actually true either, or not true for the reason you assume. I'd say I've seen about 5-10% of public mask-wearers with more-available KN95s, which does count as "common" (just not ubiquitous). N95s were extremely unavailable for a long time, but early in the pandemic, I saw at least that much N95 use (given lots people like me probably had a few laying around, that then got used up).

I am referring to actual NIOSH N95s when I say N95. They are certainly used by a slim minority of people on the street, and I am not stating otherwise. However, their lack of comfort is a reason many people would/do choose not to wear them. In the context of use by the general public, I'm implying that it is not really practical to expect mass use of (or mandate) N95s. It would not be received well, and they wouldn't be used properly anyway. In a world where we're struggling to convince people to cope with the inconvenience of wearing surgical masks -- you're definitely not going to convince them with a NIOSH N95. KNs/FFPs are reasonable compromises, and they're downright cozy by comparison.

KN95 masks are just rebranded PM2.5 masks that Asians wore mostly to avoid pollution particulates.

> paint aerosols.

A warning/clarification here - N95 masks will not protect you against paint fumes. You should never use them when spray painting. You need a respirator with a charcoal canister.

That said, even with a proper respirator it's really hard to get the fit right. I had a big painting project two years ago and I could often smell the paint, which means it wasn't working.

> Is Austria on a different track when it comes to the epidemic? Not really. Where is the 75x protection?

Well, the article claims 75x protection when you wear an N95 mask. Are all families in Austria wearing N95 masks when at home with each other? I doubt it. Unfortunately there are many, many opportunities for infection: like at school/daycare/work then bringing it home to your family. Wearing a mask while shopping is probably a good thing (it certainly can't hurt!) but 75x mask protection is never going to lead to 75x fewer COVID cases.

If you read the book "The Design of Everyday Things" you'll find a chapter on error. Human error is a thing and if it's a common error it's a design error.

N95 masks need to be worn correctly. If we wear them improperly they loose their ability to do their jobs. Nurses I know have had training classes on wearing them properly. It's not obvious or just works.

I was in a school board virtual meeting earlier this year. When it came to the open comment period in the meeting a nurse go on and politely shared the number of times the school board members and errored in their use of the masks.

So often the mask guidelines and expectations of their effectiveness are based on the assumptions people will wear them properly. Sadly, that's just not the case.

> If we wear them improperly they loose their ability to do their jobs

That's not true. They will just have lower efficiency. This study itself tested the effect of not fitting the mask (not even adjusting the metal nose bridge), and the effect was not dramatic.

It's like saying "if you don't wear your mask 100% of the time, you might as well not wear it at all, since you could be infected in the 1% of the time you don't wear it.

> "if you don't wear your mask 100% of the time, you might as well not wear it at all, since you could be infected in the 1% of the time you don't wear it.

This all depends on what the goal is. If your goal is to mitigate individual risk then 99% is better then 0%. If your goal is to never be exposed to the virus (immunocompromised, can't be vaxxed, comorbidity, etc...) then you arguably should not participate in something that requires you to remove your mask in public even 1% of the time. If you're a government trying to limit spread/hospital load then even something 20% effective will have an impact across an entire population.

If the virus you're dealing with is so incompetent at spreading as those strains from early 2020 were that almost failed to reach R=1 despite being fully airborne (which we now know, but back then even experts fell for "airborne spread could not possibly be as slow as we observe!"), even something like 5% effective can be a swim or sink difference for the virus.

That said, we are now in the omicron era and things are very different now (masks are a weak but nonetheless important tool for the project of "please take turns with sick leave, thank you very much", and nothing more, nothing less)

Even medical professionals don’t mask properly — and I’m talking at big medical centers run by the largest HMOs in the US.

It’s not hard to wear an N95 correctly. They come with a manual and the CDC has plenty of supplemental information.

What’s more important is people being disciplined enough to use them correctly all the time.

Plenty of people are wearing masks because the sign says you have to or “no groceries for you”. That category of mask wearer is not going to carefully read a manual plus the CDC supplemental information on how to properly overcome the hurdle standing between them and their family’s groceries. I count it as a win if that person’s nostrils are not visible around their cloth mask.

I was in the Knoxville airport this summer and after five minutes of seeing a litany of pointless choices people had made with masks, I wouldn’t have been the least bit surprised to see someone wearing a mask that was partially covering their eye.

Well when I was in Houston I saw several men in the airport wearing ski masks. I don’t know, I guess they feel regular masks make them look sickly or effeminate or something.

> No actual controlled evaluation that measured protection against the actual infection has ever found effect remotely as strong

Such a study does exist:

> Upgrading face masks to filtering face piece (FFP3) respirators for healthcare workers on covid-19 wards produced a dramatic reduction in hospital acquired SARS-CoV-2 infections, according to research carried out at Addenbrooke’s Hospital in Cambridge.

> Once FFP3 respirators were introduced [as opposed to simple surgical masks], the number of cases attributed to exposure on covid-19 wards dropped dramatically—in fact, our model suggests that FFP3 respirators may have cut ward based infection to zero.

https://www.bmj.com/content/373/bmj.n1663

Its dumb approach when you look at it from a bit bigger distance. The solution to protection isn't just focusing hard on as-good-as-possible masks.

People do mistakes with masks (often intentional), forget to wash hand after firmly holding door handle that was touched by 1000 other hands on that day. People have small kids which is a vector you have practically no control over. People do family visits where all masks go off. Folks go to restaurants and as soon as they have drinks everybody acts like covid disappeared suddenly.

I firmly believe average human is simply not mentally equipped to keep constant vigilance and cover all potential routes. It tires everybody rather quickly.

As for N95 masks, neighboring Slovakia has them mandated for quite some time too and it didn't prevent them being 2nd worst globally in new cases few months back. Why? Well 50% of population not vaccinated is a good start. Opposition politicians in good old Trump manner attacking any covid measure government puts in or science in general, generating a large pool of antivaxxers over time. Bravo, that's one sure way to get a lot of blood on your hands without ever pulling a trigger.

I really see omicron as kind of godsend within limits of current situation - I would cancel all measures and open everything, brace for a month and let it run through populations. This prolonged agony and ineffective lockdowns that prolong general agony ad infinitum wreak havoc on kids and tons of professions, and frankly on almost everybody in some way.

Also in general who the fuck wants to live thinking about a mask all the time?

What is the denominator?

Also notable is that proper use of an N95 takes training. Unlike with surgical masks, N95 fit is specific (you normally get them sized when issued at a hospital). In addition, most people have bad habits around mask removal - you should always remove masks by the bands, but people tend to touch the mask surface itself. And with any mask removal, you should always wash your hands (in a particular manner that I'm sure readers are familiar with by now). Finally if, when removing a mask, the user touches the interior of the mask after touching an infected surface then reapplying the mask can lead to infection.

Not doing any of these steps can lead to infections. Simply issuing N95s to a general population might not help, if the population is improperly trained.

Surgical masks "work" by preventing the wearer from spreading diseases to others. In aggregate, this can help a population, but in specific cases it might not protect you. N95s work by protecting the wearer, with only secondary benefits to others (the N95s with "nozzles" on the mask surface provide no protection to other parties, as outflow is unfiltered).

The fit thing is difficult, because actually do it properly requires specialized equipment. But for the general population, worrying about that may be letting the perfect be the enemy of the good.

The rest of it is actually pretty easy to learn. Here's a two-minute video that explains it: https://www.youtube.com/watch?v=zoxpvDVo_NI

In case anyone is interested, the fit test procedures are documented here: https://multimedia.3m.com/mws/media/252309O/3m-adflo-qualita...

IIRC, that's one of the two methods they use. The "qualitative" gives a binary result, but there are also "quantitative" methods that measure the the actual filtration efficiency with the fit.

That qualitative test kit is probably the cheapest, but it still costs still hundreds of dollars. Though I imagine that's mainly due to low-volume production, since it doesn't seem that complicated.

There are some options for doing fit tests with cheaper equipment. Here's one that uses a humidifier and essential oil diffuser and compares them with the official testing equipment:

https://www.cambridge.org/core/journals/disaster-medicine-an...

Surgical masks also require training. Many people wear masks below the nose. It's often said that this is "malicious compliance", but I've seen them do it outside, in times when even wearing them inside wasn't mandated.

I don't think you can take one number and then say that X measure is wrong.

AGES says that over 60% of infections where in a private setting, e.g. the kids/parents get sick and then they meet friends.

https://www.ages.at/themen/krankheitserreger/coronavirus/epi...

So it seems that the ffp2 measures are working.

> Yes, mask may work in some circumstances, but everyone wearing them all the time in social settings?

I found it pretty obvious almost two years ago already that N95s are pretty good at filtering particles (even smaller than rated) and that most people are pretty bad at using them consistently. Further evidence is great, but I wonder if people really are surprised to find this out.

One thing should have been obvious to everyone at all times: You cannot eat while you wear a mask. People take their masks off all the time to have a meal together. What's the point of wearing a mask for the rest of the day then?

>Is Austria on a different track when it comes to the epidemic?

Austria and Switzerland have shockingly high vaccine skepticism rates when compared with other advanced European countries like Ireland or Denmark.

I have no explanation for why this just that when they were measuring vaccine skepticism Switzerland and Austria were up there with Romania and Bulgaria and I was spitting out my coffee at the chart.

So it could be N95 masks are effective but other mechanisms are letting down these populations.

> Switzerland and Austria were up there with Romania and Bulgaria

Austria has 73% of the population fully vaccinated, Switzerland 67%, the US 62%. Romania has 41% and Bulgaria 28%. Not at all the same.

New variants are much more contagious, people don't wear masks all the time.

Not wearing masks in all social settings is more a cultural thing than anything else. Just take a look at the streets of Tokyo now: someone without a mask is a pretty uncommon sight.

The important part is buried:

The fit of the mask is the most important factor, Bodenschatz, said. “It turns out that leakage dominates over filtration.” Masks should have a tight fit around the face and nose to minimize any air leakage.

I switched to N95 some months ago after being called back into the office. It is incredibly clear upon first wear that air has a much great chance of going through this style mask instead of around it. Basically, if the mask fabric isn't slightly inflating and deflating on each breath, you're wearing it wrong.

It's stunning to me that literally billions of pounds are being spent on now futile testing without getting this basic stuff right.

I'm skeptical of any ear-loop design (although I wear them myself in relatively benign environments such as Costco). For "hot" environments such as airports, shuttle busses, airplanes, I've switched to the kind that has bands that go around the head. The difference is profound: when taking the mask off you notice that there are _smells_ that have been filtered by the mask. Never had that experience with the ear loop kind.

An airplane that has constantly filtered air is a hot spot but Costco is relatively benign?

Your risk calculus is out of whack.

Dispersion matters, as does exposure time. A single inhalation of recently expelled air can be enough. You might waft past someone in Costco, but you could be sitting in the air current of someone shedding virus particles for hours on end, even if the particles are eventually being filtered by A/C.

Open the vent above you and point it at your face.

I have seen airlines discourage that. I wonder whether it makes things better or worse (or whether it is some sort of prisoner's dilemma - making it better for yourself, but worse for others?).

Really? Admittedly I only fly Delta, but they've certainly never discouraged it. Also, I don't really see how it could make things worse for others, since it would also be pushing any viral particles you may be expelling towards the floor where the intake vents reside.

> but you could be sitting in the air current of someone shedding virus particles for hours on end, even if the particles are eventually being filtered by A/C.

Airplane air turnover is _extremely_ high, apparently even higher than many specialized hospital environments. If there's any danger, I would imagine that it would come from the immediate airflow within the cabin, and not from gradual saturation of the cabin's air.

I don't actually have a good model of airplane risks. But I recognize that many of my intuitive assumptions about what's going on would need to be checked against real data.

> An airplane that has constantly filtered air is a hot spot but Costco is relatively benign?

An airplane where you are packed in with other people in a small tube close enough that you are essentially (and often actually) in physical contact on one (or both if you are neither in a window or aisle seat) side is a hot spot, but Costco where you are moving, everyone else is moving, there are wide spaces where you don't have to be particularly close, and high ceilings and wide bay doors so it's essentially outside, is relatively benign.

> Your risk calculus is out of whack.

No, yours is, unless you are on some weird airplanes where everyone is wearing a breathing mask so that the constant filtration happens before your exhalation gets all over your neighbors.

That’s why N95 masks don’t permit ear loops, as far as I understand. The KN95 masks (similar certification from China) fill this purpose for people that really want ear loops, but I also find that they’re decidedly trickier to fit on my face than headbands.

I think a lot of this comes down to personal fit. For example, I have three sets of masks:

- NIOSH certified N-95s with a head band. These are just about impossible to keep from fogging my glasses. The long elastic seems to "fatigue" after an hour or so and I can't keep a seal.

- Good KN-95s sourced from an allegedly trustworthy source. These seal much better around the nose, but they tend to leak under the chin.

- KF-94s (chosen after trying on multiple brands). These use ear loops, but they seal very tightly around the nose, and they seal tighter than the KN-95s at the bottom. They do occasionally leak a small amount of air at the bottom.

I suspect that as long as you're using certified, authentic "94+" masks with good filtration ratings, the biggest remaining factor is how well a specific mask seals for a specific person.

> The difference is profound: when taking the mask off you notice that there are _smells_ that have been filtered by the mask. Never had that experience with the ear loop kind.

I notice that with KN95 ear loop masks consistently.

That's interesting. Now I want to try to cook some onions with a mask on and see what I can smell - although I know aromatic compounds are pretty small.

That’s what I tell my kids (tweens): if you could smell their fart, you could catch their COVID.

And if you're vaccinated, you're protected. So stop worrying about masks.

Also, you're kids, so you were at extremely tiny risk in the first place.

> And if you're vaccinated, you're protected. So stop worrying about masks.

Better than not vaxxed, but with Omicron not nearly as well protected as against prior strains, and with both Omicron and Delta not protected against infection and retransmission enough not to be a public health risk if unmasked, even if your personal risk is low because of your combination to age, vaccination status, and general health.

> Better than not vaxxed, but with Omicron not nearly as well protected as against prior strains

...against symptomatic infection. The vaccines still provide excellent protection against severe outcomes. There is no debate on this point.

> with both Omicron and Delta not protected against infection and retransmission enough not to be a public health risk if unmasked

The vaccines still reduce risk of infection by 30% (if not more), even against Omicron. You need only look at the statistics from a state that breaks down by vaccination status to see that this is true. As of right now, the unvaccinated in NYC have a case rate of 3292 per 100k, and the vaccinated have a case rate of 457 per 100k -- a seven-fold reduction in risk of infection.

https://www1.nyc.gov/site/doh/covid/covid-19-data.page#daily

Masks are nowhere near this level of effect size. Worrying about masks after vaccination is the ultimate bikeshed. You've already done the thing that slashes your risk, and you're fixated on the thing that has almost zero evidence of effectiveness, because it's the thing you can see.

> Masks are nowhere near this level of effect size. Worrying about masks after vaccination is the ultimate bikeshed.

It's not a bikeshed; it's an easy, cheap action with added benefit, not a way to waste time dithering that impedes useful work.

Yes, it's much lower value than vaccination, but that only matters if you treat them as alternatives, which they aren't.

> it's an easy, cheap action with added benefit

Prove it. Cite one study that shows added benefit after vaccination. Not a lab study. Not a study on rats or ferrets or mice or mannequins. A controlled study of humans, who are vaccinated, who are wearing masks in the real world.

You've had two years now. It's time to stop making things up, and back up your claims with data.

General agreement.

One correction: Airplanes are safer than Costco.

When I first read the claims about air exchange rates on airplanes, I thought it was corporate propaganda. I looked at the research. Flying is authentically pretty safe. The air gets cycled and scrubbed insanely quickly. There's still a risk, but it's safer than Costco.

If you do need to travel, you want to be paranoid exactly at airports and similar. The flight itself is not so bad.

There was a flight a while back, where everyone wore masks (cloth or surgical) and had some crazy number of people with COVID on-board, but no in-air spread.

Sample size of one, but every.single.time I fly long haul, I get a cold.

While it is certainly possible you got sick on the airplane itself, don't factor out the trip to the airport (cab/public transit) and all the different crowds your have to deal with at the airport itself. I know airport staff do the best they can, but during particularly busy travel times airport bathrooms can be incredibly disgusting in my experience.

Aye, it's far from certain it's happening on the aeroplane itself, but I've assumed it is because the air is so dry, and because I was always travelling in business, using lounges with nice toilets, not being next to other people outside of the plane etc.

I think you are underestimating how often business class people are traveling slightly ill

Sample size of many, but correlations doesn't imply causation.

Evidence for limited spread on airplanes is pretty solid, but everything from here on out is speculatory:

* A lot of people get sick traveling. You're interacting with all sorts of people from far away who have novel viruses, many of which aren't circulating in your area. That doesn't mean you catch it literally on the airplane.

* Masks probably make a bigger difference on airplanes than elsewhere. Even cloth masks catch big particles. By the time droplets evaporate into small droplets, odds are they've passed through a HEPA filter many times.

If travel is stressful, or causes you to get less sleep, (etc) that may also affect your immune system.

In addition to the other responses, plane cabins have very low humidity, which can take out your mucosal protections from getting a cold. It's really common to at least have a scratchy throat after flying just from dryness, and often times catch a cold afterward.

Yes, I think this is probably what does it - my nose and throat always feel really dry after a long flight, actually I almost feel dehydrated.

Rhinoviruses spread not only via aerosols, but also supposedly spread better through surface contact than COVID19. Air circulation won't stop you from touching a contaminated surface.

But its pretty clear medicine has a very poor understanding about how viruses spread given how long they denied coronaviruses were airborne. So who knows.

> There was a flight a while back, where everyone wore masks (cloth or surgical) and had some crazy number of people with COVID on-board, but no in-air spread

Anecdotal but my friend had taken off his mask for 5 minutes for eating during a flight (this was during India's massive wave) and he got infected. Almost everyone would have been wearing a mask (unless eating themselves). Off course it's possible that masks are incredibly effective (and I'm not doubting that) but I'm not convinced aircraft filtration systems are that top tier.

I'm wondering how you/he was able to determine that he got infected during, rather than before or after the flight.

Because before that he was in his university's hostel that had cut off outside access for several weeks, and while he isolated after coming home he got sick about 4-5 days post his travel. Of course this is what he told me so there's some data loss but he emphasized heavily how he was practically always masked except for while eating.

Intuitively, it doesn't make sense to me. How do they scrub the microscopic particles containing sars-cov-2 and how do they recirculate my breath before it gets to the guy next to me?

They don't need to.

Omicron aside, peak infection rates were around 30 cases daily per 100k. The odds of the guy next to you having COVID were always very low. The odds of someone in the same building, airport, plane, bus, classroom, workplace, etc. having COVID were often quite high.

Airplane filtration systems mean you /only/ have to worry about the guy next to you, and not about everyone else on the airplane. That's pretty low risk.

The other curiosity about COVID are superspreaders. Most people don't spread COVID very much. A few people spread COVID /a lot/. The question isn't just whether you're sitting next to someone with COVID, but whether you're sitting next to a superspreader. If the person next to you has COVID, but isn't shedding a lot of virus, you're probably okay too.

That said, the guy next to you likely isn't shedding microscopic particles, but pretty large droplets. Your mask stops large droplets pretty well. The airplane filtration system just needs to get them before the become microscopic particles.

Planes don't really do much filtering, and air "recirculating" in a plane is largely a myth.

Rather, some of the air going into the big fans of the engines is diverted into some air conditioning machinery that gets it to a comfortable temperature and humidity, and then pumped into the passenger compartment. In order to maintain the correct pressure, there are basically "leakage" valves that let air flow out of the plane. An airplane maintains pressure by balancing how much air is allowed out of that valve vs how much air is coming in through the AC machinery. The result is the vast majority of air inside of a plane at any time is air that was previously outside the airplane.

> Rather, some of the air going into the big fans of the engines is diverted into some air conditioning...

To be pedantic, modern bleedless engines don't do this but just directly get fresh air :)

> I've switched to the kind that has bands that go around the head ... when taking the mask off you notice that there are _smells_ that have been filtered by the mask

What kind of respirator have you switched to? Smells are vapors and not particles, so they're removed by eg activated carbon and not particulate filtration. I would bet your better respirator has "nuisance organic vapor" protection or something like that.

For example, with my 3M silicone facepiece [0] you can use a 2291 filter (no OV), 2297 filter (nuisance OV, what I use for Covid), or a 60921/6001 for full OV which blocks any smell I've come across (in addition to protecting against hazardous levels of some specified organic vapors).

[0] https://multimedia.3m.com/mws/media/40744O/3m-respirator-car...

Not being able to smell noxious smells is one of the few upsides of wearing a mask.

I've been using different P100 masks since the beginning of the pandemic and while it occasionally garners strange looks, I love not smelling anything when forced to use a port-a-potty.

> The difference is profound: when taking the mask off you notice that there are _smells_ that have been filtered by the mask.

I think wearing a mask has made me more sensitive to smells. So one of the things I like about masks is not having to smell other's bad breath occasionally or those closed air conditioned spaces that have "humid" smells.

Presumably these tests were performed with well-fitted masks, or else it would seem inconsistent to claim both that N95 gives a dramatic improvement and that leakage dominates. Personally, I have yet to find a disposable mask, whether N95 or not, and with a nosepiece, that fits well enough that my glasses don't fog up when I go indoors (they do, however, meet the inflation test.) This leaves me unsure how much better N95s are in my case, though I will continue to use them.

When I worked shifts in a vaccination center, I used medical tape along the top edge of the masks I wore.

Maybe my nose is funny or I'm just dumb but I've never managed to get any of these cheap masks to seal well enough over the nose that my glasses don't constantly fog up when it's cold. (workaround: act like they're reading glasses)

No problems with reusable half-masks with their flexible rubber seals, though those are kinda impractical for the purpose of papers-please-compliance.

What has worked for me: put the nose bit of the mask _high_ up on your nose, then do the usual thing of shaping the metal bit to your nose firmly, kind of try to shape the sides in just a bit, then put glasses on. You don't want to go too crazy, too squished if anything is worse than too loose.

It's basically a pain in the ass but it works for my particular face anyway. I can now, 9 times out of 10 fit it well enough that my glasses won't fog, and with n95, there's no evident leaks.

I find a model of kn95s that fits well with a minimum of fuss. I’m often surprised by smells in a room when I take it off. In comparison, a hospital supplied n95 my wife had was terrible to get to fit for my face. If you try one and it’s difficult to get to fit, try a different model. They’re not all the same.

Try KF-94s, there are several high quality korean brands on Amazon. These are the ones that are curved instead of beak shaped in front of your mouth and nose, giving you extra room to exhale. These never fog up glasses if you fit them properly.

Def liking my new kf94’s

They were tested with both poorly fitted and well fitted FFP2s.

I recently got some masks from Home Depot that work really well with glasses; they are 3M Aura Particulate Respirators (N95). Nice nose piece, and they are designed to direct the airflow outwards/away from glasses/goggles.

Edit: Found the link - https://www.homedepot.com/p/3M-Aura-Particulate-Respirator-N...

When I wear an N95 regularly I make sure to shave around my chin and beard. If I don't then I can feel all the airflow going through there instead of the filter material.

Most definitely.

Most of the time I don't even see people wearing their surgical mask properly. Hell, I just went to a medical clinic, and the assistant there didn't even press the nose wire completely against the nose.

And that's not counting the chin diapers, nose rhinos, and the countless people taking the mask off by pulling on the outside of the mask instead of taking it off from the ear loops.

Don't let perfect be the enemy of the good.

>“It turns out that leakage dominates over filtration.” Masks should have a tight fit around the face and nose to minimize any air leakage.

Wasn't this exactly what people against mask mandates were ridiculed for saying? That most of the cloth masks were effectively just for appearances because they didn't form a seal around the sides of your mouth? I vividly recall people being mocked for suggesting this early in the pandemic. Seems like governments were just trying to cover for the fact that N95 masks were in short supply

Anti-maskers weren't being condemned for pointing out that ersatz cloth masks weren't very effective. They were condemned for levying that criticism as if it was a justification for doing nothing, as opposed to an argument for more effective off-the-shelf respiratory protection.

(I ignored your attempt to drag "mandates" into this, because the primary aspect is personal behavior. I've yet to see an anti-mask-mandate protest/movement where everybody voluntarily wears respirators and distances, while philosophically arguing against legal mandates for doing so. And I would remember if I had, as this would align with my own politics)

But none of the mask mandates--at least in the USA--have required masks that significantly work. So you have a law that requires uncomfortable masks that make it hard to communicate, but don't significantly reduce transmission. "Well some masks do work!" is not a good counter-argument, especially when its clear that nobody really expects the public to be able to wear the good mask the correct way.

You are asking them to respond to an argument the pro-mask contingent was afraid to even make.

Yes, the mandates as they currently stand are lame. But the anti-maskers are using that senselessness to argue for rejecting the whole idea of wearing any respiratory projection, which they demonstrate by personally choosing to not wear respirators. As I said, their argument is not akin to "respirators protect against the spread of Covid but the government shouldn't be mandating specific personal behavior", but is rather rejection of the whole subject.

For an illustration of the difference, I recently had some trouble entering a hospital due to their mask mandate - they seriously insisted that I take off my P100 respirator and wear just their cosplay mask instead. I was able to escalate to someone higher up and find a (more but still not entirely sensible) compromise that they'd let me wear my own N95 under a cosplay mask. Where is the political group that represents my predicament, which was caused by a broken centralized mandate? It's certainly not in the unmasked people berating customer service people for enforcing some basic pandemic etiquette!

> nobody really expects the public to be able to wear the good mask the correct way.

IMO this was a terrible groupthink counterargument (aka straw man) led by the other political team of ersatz maskplayers and condescending healthcare workers, following from the early central authority lie that respirators are ineffective (in order to reduce consumer demand for them). The red herring that wearing a mask primarily protects others also followed from this rationalization of ersatz cloth masks.

The open society / freedom approach is that you treat people like adults, assume they can understand a mildly complex thing, and then increase education to help everyone do better. Instead two years later we've still got the two political teams arguing over which stupid approach is better, while mostly looking at anyone who wears more effective respiratory projection as some aberration.

If I had been in charge of pandemic response, I would have sent everybody a kit including a N95 mask as soon as possible, and made it clear that the primary reason to wear a respirator is to protect yourself and your family. Then I would have ramped up production of elastomeric half face masks (which are more comfortable and thus more sustainable), and perhaps just given those out as well - their (pre-pandemic) cost of $30 per person is peanuts compared to what we've lost. These utterly backwards post-reality memes spread by both political teams have caused so much needless death and suffering.

There was an episode of Dr. Oz from April 1, 2020 that demonstrated exactly how difficult it was to properly fit an N95.

The surgeon general released the demonstration of making a cloth mask from household items on April 4, 2020.

https://m.youtube.com/watch?v=9YLXEhSjVsw

Fauci on February 5, 2020 wrote in an email:

> The typical mask you buy in the drug store is not really effective in keeping out virus, which is small enough to pass through material. It might, however, provide some slight benefit in keep out gross droplets if someone coughs or sneezes on you.

Protection was and still is marked at a percentage less than 100% but still useful. The people being ridiculed were saying there was no point because it’s not 100% without realizing that the lowered percentage or ratio of spread when BOTH parties are wearing even an ill fitting mask. The difference is not negligible. It’s really a math equation between two social parties in the end. People wearing masks often lower their protection even lower because they wear the same mask every day or after every exposure without washing or by constantly touching it.

In general, I disagree with the “ridicule” but instead, trying a new or different way of explaining it.

Let's do the math. Assume the protection is 90% for each individual interaction. After 7 interactions you're down below 50% protection. And people in the real world obviously aren't going to stop interacting.

According to this study, with two people talking 3 meters apart and one infected, if only the non-infected person wears an ordinary surgical mask (not n95), it increases the time to the 90% bound for infection risk from 1.5 minutes to 30 minutes. So at least in theory it's certainly not for nothing.

> most of the cloth masks were effectively just for appearances because they didn't form a seal around the sides of your mouth

I remember people saying that, but I had always understood the primary benefit of cloth and other masks was to limit the wearer's ability to spread virus-containing droplets if they were infected by asymptomatic (or symptomatic and very reckless, I suppose). I thought it was widely acknowledged that they provided very limited protection for the wearer. "My mask protects you, your mask protects me." This is why, for example, there were recommendations to not wear vented N95 masks.

Of course, the fact that the mask doesn't form a tight seal around the mouth surely undermines its ability to provide both forms of protection, to some degree. But I seem to recall a fair amount of discussion of the fact that masks could still be fairly effective at reducing the number of virus-containing droplets expelled into the surrounding environment even in the absence of a tight fit. (And, for what its worth, that has always made fairly intuitive sense to me. Though I acknowledge that's not a very good reason to believe it.)

Maybe others' experiences differed, but I thought this was very clearly explained by the 'authorities.' Though that didn't stop people from misunderstanding or, in some cases, spreading misinformation to score political points by making mask proponents look stupid.

An N95 is the opposite. It only filters on the way in.

Which is the direction we should be going, anyway. High risk people who cannot get vaccinated should wear an N95.

Edit: As numerous people have pointed out, this is wrong. All the N95 masks I’ve seen had a valve, but apparently this is uncommon. TIL.

I'd actually like to see the data on the degree to which N95 masks also reduce the number of virus particles expelled. I'd be pretty surprised if an (unvented) N95 really did little to block virus particles from being expelled, even though that's certainly not what they are designed to do.

But, in any case, its consistent with my point that, supposedly, there are benefits to cloth masks, even if they don't fit tightly around the face. That's not to say it wouldn't be better if everyone wore an N95/KN95/etc.--especially people who are at high risk.

It's going to come down to the ventilation of the space you're in regardless. We're back to square zero: improperly ventilated indoor spaces are a huge public health concern, even beyond covid.

Ventilation is certainly important and I'd like to see much greater focus on this. But, to state the obvious, we're not going to improve the ventilation of existing spaces overnight, unfortunately, so we also need to figure out how to mitigate risk in the meantime.

> It only filters on the way in.

Absolutely not? How would that even work. A well-fitting half-face mask has virtually no leakage when breathing in or out.

Yes, thank you. I had incorrect information and edited my post.

That’s only for the versions that have an exhalation valve, which people shouldn’t be using for COVID.

> An N95 is the opposite. It only filters on the way in.

Only if they have a valve. Masks with valves are usually considered inappropriate for covid.

All valveless masks, including N95, surgical and cloth masks protect both ways, there is no difference between the front and the back of the filtering material. Some masks are better than others, but none are one-way unless there is a one-way valve.

That's also a reason why they recommend N95 and not N99. Most N99 masks have valves (can be uncomfortable without them) and are therefore inappropriate. These are mostly to protect construction workers from harmful dust.

The valve masks are designed for industrial use, like sanding or spray painting. Until 2020 those were the ones you’d see the most, since they’ve been readily available in home improvement stores for obvious reasons.

And if cheap cloth/pseudo-surgical masks don't capture any exhaled droplets, I'd really like to know how they get so wet and gross while I'm wearing them.

Well they do catch droplets, but only enormous ones that would fall almost immediately to the floor.

We really need to be honest with people about masks and stop pretending like they do anything if they aren’t at least surgical, clean, and fitted correctly on the face.

> ridiculed for saying

> That most of the cloth masks were effectively just for appearances

Yes, because it is fallacious to say `if(protection < 100%) { masks are not useful }`.

Any level of protection is better than zero. We really can't afford to all wear PAPRs, and wearing the best that we can get is always the best solution. When (K)N95s were in short supply, the best we could reasonably have everyone wear was cloth.

If you always want the best protection do you also wear a crash helmet and fire resistant suit whenever you ride in a car?

That is the criticism I am making.

Well I think when we start seeing Cybertrucks everywhere you will know that people really are trying to dodge bullets and run over homeless for their own safety.

When I'm driving in a low risk environment, e.g. around town, no. When I am in high risk environment (i.e. racing on a track), yes, these are required and you won't be allowed on the track without them.

Walking around a grocery store is now a high risk environment.

> "It turns out that leakage dominates over filtration."

That sentence does not translate to "cloth masks are useless". In comparison, a bullet-proof vest may only protect part of your body from danger but it's still better than nothing if you're being shot at.

I guess if bullets could flow around the vest and then still hit you, that analogy would work.

What you've basically said is that if a mask is not 100% effective it's useless. My analogy stands, just because a bullet-proof vest is not 100% effective in stopping all bullets from hitting your body, it doesn't make it useless. Some protection is better than none.

Has there ever been a study that shows whether face masks work when used in public with COVID? I keep looking, and I find it kind of incredible that we're two years into a pandemic, and except for one study in Bangladesh with masks (that wasn't really that clear) - there is nothing to say that any of these masks are working.

There are a bunch of studies with the Influenza virus (different virus) and surgical masks in school settings, both with and without disciplined hand washing - and the meta-analysis of those studies suggests that masks (not N95) - don't really do much to prevent transmission of the virus.

I religiously wear my 3M 8210 N95, tight enough to leave welts on my face and indentation in my skull - so clearly I would like to believe it's helping - but I would kill to see a good Randomized Control Trial. Obviously wouldn't be double blinded - because of course you would know you were wearing a mask - unless you gave one cohort faulty masks, and the other ones actual filtering masks.... The ethics of doing this with Covid are obviously questionable, unless you could find a group that had already made the decision not to wear masks...

Randomized Control Trials are not the one and only way to prove something.

> Conclusions: Parachute use did not reduce death or major traumatic injury when jumping from aircraft in the first randomized evaluation of this intervention. However, the trial was only able to enroll participants on small stationary aircraft on the ground, suggesting cautious extrapolation to high altitude jumps.

https://www.bmj.com/content/363/bmj.k5094

Sure, they're not the only way - but they are definitively the best way, and nothing is stopping this kind of study from happening, especially in low risk (age) groups / populations.

I think it might even be ethical if you could find such a low-risk cohort that was adamantly opposed to the wearing of masks, and under no circumstances whatsoever, except perhaps because they are scientific minded individuals and would like to prove they are not required, would wear them.

Yeah I think there's a few million of those in the US

Given other beliefs those people are likely to hold, at least here in the US, I suspect there would be some other behaviors they would be systematically more likely to engage in that would act as confounds.

Not a statistics expert by any measure (I'm sure many people here are) - but doesn't effect size play a role here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5878948/

If N95 masks in a virus laden environment are akin to parachutes when falling from an airplane - that's great news. I'm super happy to be educated on this given my unbroken record of never having been indoor in 18+ months without one. Happy to know that it's been making an absolute difference.

https://www.bmj.com/content/373/bmj.n1663

FFP3 is a bit better than N95 (it's equivalent to N99).

N95 masks came from industry, but there were no RCT studies there. People just noted that they obviously worked, through arguably one can easily feel that a saw dust mask works as opposed to one against viruses.

I wonder if an N95 that's been tested to filter 99%+ is roughly equivalent to a FFP3? https://www.armbrustusa.com/pages/mask-testing?mask=-review

I've done extensive research on this subject, for coronavirus purposes N95 is equivalent to FFP3. The most important aspect is having head bands (as opposed to ear loops) to secure a tight fit. N95 typically have head bands. FFP2/KN95 (filtering equivalent to N95) typically don't, which is why FFP3 are sometimes preferred. There are also regulatory reasons to use FFP3.

3M also manufactures FFP3 masks. Not sure if they sell them outside EU though.

https://www.amazon.co.uk/3M-9330-Aura-Unvalved-Respirator/dp...

That "one study in Bengladesh with masks" involved 342,183 participants and produced clear evidence that masks work. What is the point of more studies if folks are just going to dismiss them out of hand?

That's not what I have been reading about the study. The evidence seems to be on the pro-mask side, but it does not appear to be _that_ clear. I'm not an expert in masks, health, or even statistics, so I'm not here to say you are right or wrong. I'm just pointing out that there is a debate. That itself is enough to want to look for more studies, don't you think?

To answer your question, the point of more studies is to increase confidence in our opinions and decisions, make better findings, realize errors, etc. And you are quickly jumping to conclusions with "folks like you are just going to dismiss them out of hand".

Now, my question would be: what do you mean by "folks like you"?

Have you looked at the study itself? From the abstract: “Mask distribution and promotion was a scalable and effective method to reduce symptomatic SARS-CoV-2 infections.”

The existence of “debate” doesn’t mean anything. Anti-maskers are always going to dispute studies like this, no matter how clear the evidence

Have you looked at the study itself? It found that cloth masks do nothing and surgical masks help a tiny bit. (control: 8.60%; treatment: = 7.63%) I suppose you could parse this as "masks work", I parse this as "if you are really worried about airborne virus, wear N95."

Page 12: "no statistically significant effect for cloth masks"

https://www.poverty-action.org/sites/default/files/publicati...

Page 12 paragraph for context:

"We find clear evidence that the intervention reduced symptoms: we estimate a reduction of 11.6% (aPR = 0.88 [0.83,0.93]; control: 8.60%; treatment: = 7.63%). Additionally, when we look separately by cloth and surgical masks, we find that the intervention led to a reduction in COVID-like symptoms under either mask type (p = 0.000 for surgical, p = 0.066 for cloth), but the effect size in surgical mask villages was 30-80% larger depending on the specification. In Table S9, we run the same specifications using the smaller sample used in our symptomatic seroprevalence regression (i.e. those who consented to give blood). In this sample we continue to find an effect overall and an effect for surgical masks, but see no statistically significant effect for cloth masks."

> Have you looked at the study itself?

Please don’t do this here. This is against the HN guidelines. https://news.ycombinator.com/newsguidelines.html

Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that."

Don't get me wrong - the Bangladesh study suggested that masks were a good public health initiative and should be used. What it didn't do was reassure me that they were a strong individual NPI.

In much the same way that not masking was recommended early in the pandemic as a public health initiative to reserve the masks for first responders - wasn't particularly good advice for the individual.

The world has 8 billion people on it. Shouldn't we care about what helps everyone instead of what only helps you specifically?

If masking helps everyone, then you should do it, even if it somehow magically didn't help you.

So - several threads here. It’s not unreasonable to try to understand what helps globally as well as individually. Early on, when supply chains for masks were stretched or non-existent, we were instructed not to wear masks. This was good advice globally, as it reserved the limited supply for those who could most benefit from them (first responders) - but bad advice individually. If you were looking for guidance to protect yourself and those you loved, following global advice was not the best path.

Likewise, the current guidance that wearing masks - particularly if they are well fit FFP3/99%+ filtering, is good advice globally, but it’s unclear if it’s sufficient to reduce the risk down to <.1% for the individual (the point at which I would pretty much not worry about social distancing and avoiding stores, workplace, etc… I’m <65 and vaccinated, So I would be comfortable with a 1/1000 risk of catching Covid, particularly as I can usually avoid those scenarios)

The question isn’t whether masks are an important NPI - they absolutely are - particularly if we could convince people to avoid going indoors unmasked and ensuring they are wearing (and not taking off) well fit FFP3s, the question is whether that is sufficient to mostly eliminate the risk of catching Covid.

One lesson I learned here is that you really need to expand on your thoughts and not assume everyone else is already on the same wavelength as yourself.

It "produced clear evidence that masks work"...if you think a 10% reduction in the speed of transmission is "working". That's a pretty minimal return for a large intervention (30% increase in mask-wearing).

Plus, they had to throw out 26 villages with 0 infections in order to get that much of an effect. Now there is a certain logic to that, but I wager that if most of those 26 villages had been ones with the intervention, they would not have thrown them out; I'm not aware of that part of the analysis being pre-registered.

They probably don't have a non-zero impact, but it appears to be pretty small, even with a massive intervention like the one in Bangladesh.

Here's a breakdown of that Bangladesh study:

https://www.skirsch.com/covid/BangladeshMaskReview.pdf

Please don't cross into personal attack when posting to HN.

https://news.ycombinator.com/newsguidelines.html

Lazy dismissal of scientific work is something of its own epidemic on HN these days. "Ah, but this study doesn't address this laundry list of things I just made up, and I haven't bothered to look at other sources, and I probably haven't bothered to even read this study, actually." It's especially common on COVID-related studies amongst the anti-maskers and anti-vaxxers on the site, but I have been seeing the same kind of lazy dismissal on lots of other posts as well. It's effectively an evolution of the Gish gallop.

I find it both dreary and frustrating, personally, and it's not terribly surprising that people like the poster above call people out on it.

I agree. Every HN post is full of "well actually" non-experts who love dismissing the work of experts with a few sentences of layman talk.

It's endemic on HN because it's endemic on the internet because it's endemic to humans. There's no "lately" about this.

The question is, what do we do about it? Posting even worse comments, like the GP, is obviously not helping.

I like to believe that HN has at least been partially successful in holding itself to a higher standard than the internet at large, through a combination of community guidelines, overall community belief in the guidelines, and thoughtful moderation.

You could, of course, say the same thing about personal attacks: They're endemic on the internet and to humanity, but we've mainly kept them out of HN using the above measures.

Lazy dismissal is often the top comment on any given post, COVID or not. It's harmful to discussion and I would argue antithetical to the hacker spirit: If we only allow perfect airtight products/proofs, we miss out on discovery and exploration. Perhaps some guideline to avoid lazy dismissals (or something along those lines) would go a long way.

I think my comment:

I keep looking, and I find it kind of incredible that we're two years into a pandemic, and except for one study in Bangladesh with masks (that wasn't really that clear) - there is nothing to say that any of these masks are working.

Was what was seen as a lazy dismissal. I should have spent more time expanding on why I didn't think it was really clear, but the point I was really trying to get at - is that there has been a lack of experimentation, trials, research - despite the millions of lives lost and many billions of dollars spent (Trillions?) - and I was really hoping someone would respond with a pointer to such a RCT that we could all read.

Unfortunately the takeaway wasn't that we should spending more time to demonstrate that masks work, but that I was dismissing that they did. The absolute opposite of what I was attempting to do. The failure in communication is clearly mine, and I'll try and be a little more expansive in the future.

For the record, what I really should have written was,

"To date, there have been no studies that have reassured me that I could go indoors into a crowd of infected, unmasked people, confident that as long as I kept my well-fit 3M 8210 N95 mask on, that I ran < 0.1% chance of being infected by Covid. The Bangladesh Study that showed 8.6% of people in the control villages reporting Covid symptoms and 7.6% in the experimental villages, did not provide me that kind of reassurance, thought I think it provided statistically significant results that masks as a general public health NPI are effective at reducing transmission of the Coronaviruses under study at the time."

Of course - Omicron essentially reset all expectations for transmissibility.

Yeah, that's exactly where I read to, which registered as more anti-masker nonsense. Thanks for the explanation(s), and sorry for the noise.

But - I was super excited by the Bangladesh study, and spent the better part of a half hour or so trying to see if I could tease out some clear evidence that masks work. I'm insanely pro-mask, and was way ahead of the curve back in february 2020, when a lot of the mainstream was suggesting masks don't work (If that's the case, then why were we trying to reserve them for first responders in hospitals?) - and encouraged everyone I know to wear them. I've spent hours reading the Japanese Meta-Analyses of mask usage in influenza scenarios, looking for differences in Coronavirus and Influenza Virus behavior.

I have never, not once in 18+ months gone indoors where other people are, without wearing an N95 Mask (after I was able to source them ~ June 2020).

I don't think it's an exaggeration that a lot of the last two years of my life have been dedicated to both encouraging (strongly) everyone I know to wear a high-quality, well-tested N95 from a well-known trusted source, as well as scouring the internet for solid research on the effectiveness of masks.

I'm not lazily dismissing that Bangladesh study - I just came away from it not being particularly encouraged that it provided evidence that the masks / methodology presented there would shut down a pandemic by preventing transmission. I'm eagerly and enthusiastically looking for evidence to confirm my bias that masks work.

The Bangladesh study failed to produce a significant result when simpler nonparametric statistics were used to analyze the data. There were also significant discrepancies in the follow up rate between the control and treatment groups. And even if you ignore those issues, the absolute effect size (20 cases) was tiny. The effect size was expressed in terms of the relative rate of symptomatic seropositives, i.e., normalized by population denominators, which makes it appear larger and is sensitive to the follow up rate discrepancies (see above).

Ben Recht at UC Berkeley has several good blog posts on this issue: https://www.argmin.net/2021/12/01/unblinding/

I'm still baffled that every mask I see at stores says "not for medical use". It's been nearly two years and we still don't have approved masks?

I'm also seeing more and more evidence that masks that aren't N95s don't do any good. The CDC still doesn't recommend using N95s but recommends cloth masks. They're still claiming that they need to be saved for healthcare workers. REMINDER: WE'RE NEARLY TWO YEARS INTO THIS THING. Our government is pathetic.

https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-si...

To be sure, 'not for medical use' probably means that the manufacturer of the mask didn't want to pay (in money and/or effort) to go through the regulatory process to obtain an official rating; this has more to do with what the market wants (cheap masks! who cares about ratings!) than the government.

Speak for yourself. I only want to wear masks if they're proven to work. I'm not playing dress up for no reason.

I think this has been more or less understood all along, but it's good to repeat it since I'm sure there are still people who haven't gotten the message. If you're looking to protect yourself, wear an N95. They're also now easily available in hardware stores again.

The "95" in N95 represents the filtration effectiveness.

So _any_ leakage means the mask fails in it purpose of filtration.

Hence it gives "only" a 70x boost in protection, not a 100% protection cast iron guarantee.

For how long? 10 years of exposure with a leaky mask is not 70% any more, more like .05%.

It's the minimum standard, really. Most reputable N95s seem to hit over 99% in real tests.

This was lately on HN, so you can check yourself: https://www.armbrustusa.com/pages/mask-testing

That's not true: leakage decreases protection, but there's a scaling relationship rather than a complete elimination of efficacy: https://pubmed.ncbi.nlm.nih.gov/24275016/

Over a long enough time the efficacy drops to zero.

> Over a long enough time the efficacy drops to zero.

And in the long run, we're all dead.

Yes, so why are we stressing about this? Just focus on getting healthy and doing the best we can is our long term limit of capability.

Masks won't save us.

So, no need to use, buy, sell, or produce sun screen. It just increases the time you can stay outside without getting a sunburn from a few minutes to hours. Totally useless. /s

All you need is a moment of infection. A single second, one breath of air through a leak in your mask. Sunburn is not even remotely similar.

This just isn't true. Viral load matters.

How long?

Good question, doesn't it depend on environment? If you are alone in the woods, the mask will always work forever.

If you are in a small room with a dozen infected people coughing...?

Its 95% at the worst particle size for filtering which is 2.5 microns. Above and below that size they perform substantially better.

The minimum size of a covid19 carrying particle is 4.7 microns, resulting in at least 99.7% effectiveness at worst.

[1]https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC7579175/# [2]https://pubmed.ncbi.nlm.nih.gov/9487666/

Almost every single time someone links a paper on HN as evidence of their statement, it shows evidence of the opposite of their statement:

2nd paragraph:

In a study by Chia et al. (2020), SARS-CoV-2 genes were detected in sampled aerosol particles with diameters >4 μm and 1–4 μm [20]. In a study by Liu et al. (2020), SARS-CoV-2 was detected in submicrometer aerosol particles ranging between <0.25 and 1 μm in diameter via a droplet-digital-PCR-based detection method [21]. In a study by Liu et al. (2020), the maximum SARS-CoV-2 concentrations of 40 and 9 copies per m3 of air were measured in aerosol samples with diameters of 0.25–0.5 μm and 0.5–1.0 μm, respectively [21].

Chainlink fence stop sand?

>> In a study by Chia et al. (2020), SARS-CoV-2 genes were detected in sampled aerosol particles with diameters >4 μm and 1–4 μm [20]. In a study by Liu et al. (2020), SARS-CoV-2 was detected in submicrometer aerosol particles ranging between <0.25 and 1 μm in diameter via a droplet-digital-PCR-based detection method [21]. In a study by Liu et al. (2020), the maximum SARS-CoV-2 concentrations of 40 and 9 copies per m3 of air were measured in aerosol samples with diameters of 0.25–0.5 μm and 0.5–1.0 μm, respectively [21].

Are those viable virus particles? Because that's what actually matters, not the mere presence of genes. Also, are the smaller droplets as effective at transmission as the larger ones? Scanning the paper, it looks like they get smaller as they desiccate.

Why would a virus become unviable just because it's embedded in a smaller droplet?

> Why would a virus become unviable just because it's embedded in a smaller droplet?

From my scan, it looked like some of the smaller droplet sizes were due to desiccation of larger particles. As a particle desiccates, concentrations will change, and maybe they'll change in a way that makes the virus non-viable E.g., imagine a freshwater lake that contains certain amount of salt, as you dry it out it will get saltier and saltier, to the point where freshwater fish can no longer live in it. Eventually you get a salt pan.

> The "95" in N95 represents the filtration effectiveness.

> So _any_ leakage means the mask fails in it purpose of filtration.

What do you mean by that? The "95" is just a statement of its performance characteristics, which literally every well-engineered thing has quantified (and are always less than "perfect").

Now if you want an N95 to meet its specifications, it has to be tightly fitted. However it's a spectrum of effectiveness, and unless the fit is ridiculously bad, the protection factor is still going to be better than a cloth mask, e.g.:

                                                                               poorly           well-    
                       cloth or                                                fitted           fitted
    No mask            surgical mask                                           N95              N95    Perfect
   |O-------------------------O---------------------------------------------------O--------------O--------O|

Don't let the perfect be the enemy of the good.

> Don't let the perfect be the enemy of the good.

Show one study in a vaccinated population of humans, that demonstrates any real-world effectiveness of masks.

The "good" here is never quantified, nor demonstrated. It's always an inference from some mechanism.

Now add a time component of exposure to the virus.

And your graph shows 100% infection rate with every setup that has any kind of leak at some point in time.

I've been wearing N95s ever since they became affordable (again) in the fall of 2020. I don't like masks, but if I have to wear one, I'm going to wear the best one and one that actually protects me. I mean this in the general sense of all particulate filters/respirators, rather than strictly N95s.

I currently wear the 3M Aura. It fits very well, my glasses never fog up and it quite easy to breath through. I used an oximeter during a long 8hr session of wearing it and had no impact on my blood oxygen levels. I work out with these masks as well and it's fine, although I do need a bit more rest in between sets towards the end of my workout. As a bonus the headstraps don't just make it fit better, when I remove it temporarily, it sits around my neck like a scarf, rather than hanging off my ears under my chin.

The masks may be disposable, but they also last long enough. If you get 5 and wear one each day of the week, then store them in a tupperware box, you can get a week's wear out of each one. $2-3 per week to be protected is a good deal.

I've tried to give my extras away to family and friends and I've found some of them weirdly resistant. They're fine wearing cloth or surgical masks, but not these. I know there's no chance of getting everyone to wear these, but I don't think anybody should be wearing anything but.

I wonder if some city/country somewhere could supply N95s to the entire population and strictly mandate them for a month whether they could stamp out Omicron.

Auras are great, mainly because of the nose padding. It seems to be slightly anti-slip in addition to adding some comfort. What's more shocking is that they very closely resemble a design that was made specifically for consumers around 2008 for dealing with pandemic situations, but somehow we're still debating over whether masks even work 13 years later.

https://twitter.com/AbraarKaran/status/1476673083905699849/p...

I saw a comparison yesterday that claimed with a cloth mask, being in the same room with someone for 30 minutes was enough to catch Covid.

A surgical mask provided an hour of protection.

With an N95, you would need to be in the room for 25 hours.

I believe that was with both people wearing a mask

I think that stat came from a chart in this article https://yourlocalepidemiologist.substack.com/p/a-quick-note-...

Also this one: https://www.axios.com/n95-mask-protection-covid-958039c9-07f...

There’s a 5x5 or so graphic floating around of how many hours are safe in different masking situations. While I agree with the relative arrangement, there’s a risk of misinterpretation.

Early in the pandemic some claimed their interactions are short so They can wear no/crappy masks, overlooking that it’s a police officer and their entire day is made up of short interactions…

Interesting intuitive point of view. Too bad there's no evidence for any of that

The infographic is based on ACGIH's Pandemic Response Task Force[1]. The list of references for respirator/mask information is available on their site[2]. I can't speak to the veracity of the evidence provided, but there is evidence.

[1]: https://www.acgih.org/covid19/ [2]: https://www.acgih.org/covid19-references/#resp

I wish they included KN95s for comparison... I prefer them because they're easier to take on and off, and the seal seems reasonable to me (breathing in/out causes the mask to deform, so it's clearly filtering some air)

Aren’t KN95s just N95s with the Chinese standards (vs US standards) but should technically work for the same particle sizes?

GP is probably referring to KF94, the Korean standard. Their form factor is somewhere between a surgical mask or an industrial / medical N95. They are quite popular, here in HK, with people who want to protect their makeup.

Example: https://www.amazon.com/KF94-Protective-Individually-Packaged...

Technically yes, but US standards require a headstrap... which is generally tighter in my experience. I'm wondering if the ear loops reduce efficacy significantly (assuming fit is proper otherwise).

You can't really give a time like that. People with detectable levels of covid might have anywhere between 100 and 10^14 viral copies/cc in fluid samples taken from them depending on their immune system and stage of progression. Infectiousness is probably proportional to that viral load. How much fluid escapes a person into the air also varies by a few orders of magnitude depending on whether they're sitting quietly enjoying a movie all the way to singing loudly.

You can if it's an average and you're not being overly literal about it. Don't break out a stopwatch and assume you're safe if you run out of the room before the average time is up.

It's not a matter of differences you need a stopwatch for, it's that the times plausibly vary between a second and years.

On the other hand: https://www.sciencedaily.com/releases/2019/09/190903134732.h...

"A study published today in JAMA compared the ubiquitous surgical (or medical) mask, which costs about a dime, to a less commonly used respirator called an N95, which costs around $1. The study reported "no significant difference in the effectiveness" of medical masks vs. N95 respirators for prevention of influenza or other viral respiratory illness."

I really think anything less than N95, especially since the infectiousness of delta, is more a crowd control exercise than anything else on the part of people in power.

No mask mandate has ever reduced the R number or growth trajectory anywhere in the world. And no study has ever confirmed beyond reasonable doubt that cloth and surgical masks work in any way against covid. KN95 perhaps, N95 definitely, but that's fairly obvious since it actually fits on your face and has a particle filter.

I strongly believe this entire mask things is just a way for governments to make people feel like they are doing something. To make you feel like you are in control in a ridiculously out of control situation. I understand the reasons for doing that, but fundamentally it's still a lie.

> No mask mandate has ever reduced the R number or growth trajectory anywhere in the world. And no study has ever confirmed beyond reasonable doubt that cloth and surgical masks work in any way against covid. KN95 perhaps, N95 definitely, but that's fairly obvious since it actually fits on your face and has a particle filter.

Could you confirm this with a study ? This seems ridiculous

This guy seems to exist to create charts that a) show vaccination does nothing to stop Omnicron, which seems to be all recent charts or b) that demographically similar states/countries that are neighbors have virtually identical results when one has a mask mandate and the other doesn't: https://twitter.com/ianmsc/

Given how infectious Omnicron is, these mask mandates are nothing more than talismans.

He's doesn't seem very credible though. For example, there's a lot of very obvious reasons which could help explain this[1].

1: https://twitter.com/ianmSC/status/1481042778293358593

Can you tell the difference between places that had mask mandates and places that did not?

https://www.covidchartsquiz.com/masks

I don't get what the point of that quiz is. All of the example countries in it instituted their mask mandates between the first and second wave. None of them did not?

I think the numbers I saw for cloth was a modest reduction.

Surgical refers to a broad range of objects, from a slip of paper to ones with high-filtration layers. For the latter, if everyone wore them, they'd stop COVID spread. See data from Asian hospitals, Indian social workers, etc.

With omicron, it's very possible only N95 reduces R0 below 1, but we don't know that yet.

A lot of it is theatrics, but high-filtration masks do help, even with imperfect fit.

https://www.pnas.org/content/118/4/e2014564118

> Our review of the literature offers evidence in favor of widespread mask use as source control to reduce community transmission: Nonmedical masks use materials that obstruct particles of the necessary size; people are most infectious in the initial period postinfection, where it is common to have few or no symptoms (45, 46, 141); nonmedical masks have been effective in reducing transmission of respiratory viruses; and places and time periods where mask usage is required or widespread have shown substantially lower community transmission.

Are mask mandates partly about governments wanting to show that they are doing something? Certainly. Are non-N95 masks ineffective? The evidence says they have benefit.

I've repeatedly had that study linked to me when I say stuff like this. Quote from your link:

> Direct Epidemiological Evidence.

> Overall, evidence from RCTs and observational studies is informative, but not compelling on its own. Both the Australian influenza RCT and the Beijing households observational trial found around 80% efficacy among compliant subjects, and the one SARS household study of sufficient power found 70% efficacy for protecting the wearer. However, we do not know whether the results from influenza or SARS will correspond to results for SARS-CoV-2, and the single observational study of SARS-CoV-2 might not be replicated in other communities. None of the studies looked specifically at cloth masks.

So if it has a history of working with other viruses, why would you think this is a crowd control exercise and not attempting something which has worked before?

We should not looking for just any benefit and then if we see some, no matter how small, force everyone in society to do it. There are tradeoffs. For me as a parent masking young kids is unconscionable. Masks _scare_ my 18 month old daughter and she loses out on all the social skill building that comes with reading people's expressions.

I agree wit you; masks should not be worn in schools.

I think human behavior needs to be taken into account when it comes to safety measures like masks. I'm sure you can design 100 lab tests to prove that masks work, but the real world reality is always going to be different: people don't wear masks (even fitted masks) correctly.

Here's a short anecdote about how well-intentioned rules often work in the real world among non-trained people. While going to school to become a programmer, I worked in the food service industry. We were told to always wash our hands when shuffling between tasks: for instance when going from cutting potatoes to going to the register to handle peoples payments, we'd wash our hands thoroughly. This system was easy enough for anybody to come off the street and learn quickly and was strictly followed. One day a health inspector came by and started freaking out about this normal kitchen practice and started screeching that everybody had to wear gloves at all times. Of course anybody who understands reality knows how this turned out in the real world: pulling off and putting on gloves correctly for each task is a pain in the butt. What happened in the real world is people would put on one pair of gloves for hours, and go from working on the food to different tasks, including handling cash without changing gloves. As long as they were wearing the gloves at all times, they felt like they were doing the right thing. The reality is that people were just complying with the letter of the rule, but spreading far more dirt and bacteria around because of the rule.

I don't care what laboratory theory says: the real world reality of how untrained people follow rules is different. In real-world practice, masks are (IMO heavily dehumanizing) medical theater. I think masks work great when used as they're intended: by trained health care professionals doing one task in one room and properly disposing of them. Everything else is politicians ruining our lives covering their asses so the media doesn't have some clickbait headline to rip them.

It depends. Covid is a high k disease, a few people end up infecting hundreds in an afternoon, many people fail to infect the spouse they share a bed with. Partially that's behavior but partially it's people achieving very different peak viral loads as well. The protection factor of 2 or 3 you might get from a surgical mask are going to be useless in some situations but might prevent an infection in others.

My mask is N95 in public, but my main strategy is to almost never leave my apartment, which I live in alone. I think when people start talking about mask efficacy, it also depends on what you're doing with that mask. Are you only going to the grocery store once a week, or are you going out every day, to work inside a building, and going in and out of buildings all day? When they talk about a poorly fit KN95, is that on a person who runs into the gas station for 2 minutes, or someone who works at a concert venue?

> my main strategy is to almost never leave my apartment, which I live in alone.

This is incredibly sad. How many years of your life are you going to lose for a virus that is never going away? (A virus from which you are extremely well-protected after vaccination.)

Now, I don't know you. Maybe you have some serious immune compromise condition -- like a recent bone marrow transplant -- that prevents the vaccines from being effective. But if not, what are you doing? Even if you're a 65 year old with multiple co-morbidities, your risk of serious illness after vaccination is in the 1-per-10,000 range, and death is in the 1-per-100,000 range. I'm not exaggerating:

https://www.cdc.gov/mmwr/volumes/71/wr/mm7101a4.htm

I have diabetes, which makes it extremely dangerous to contract covid. I'm fully vaxxed and boosted, but Omicron breaks through vaccine protection. I also like my apartment and there's plenty to do here.

> I have diabetes, which makes it extremely dangerous to contract covid.

The paper I linked above covers diabetes. Please read it. In a population of 1.3M elderly (> age 65; aka "high risk") people post-vaccination, a total of 98 diabetics had a "severe" case of Covid (i.e. not just death). The adjusted risk factor was found to be 1.47, on a baseline of 0.015%.

In other words, if diabetes is your sole concern, it certainly qualifies as elevated risk, but in no reasonable world is a risk measured in hundredths of a percent "extremely dangerous". And remember: these are elderly people. Your risk is almost certainly dramatically lower -- if you're in the demographic of the typical HN user, divide this by ten.

I can't emphasize this enough: this virus is not going away. It will be with us for the rest of our lives. If you can't go outside now, you will never again be able to go outside.

I'm seeing things like this. I should have more specific. I have metabolic syndrome. With variants like Omicron that have higher ability to bypass vaccines, I'm not taking the risk. Covid of some sort will be with us, but hopefully it won't be at this level of risk for people like me always.

https://www.sciencedaily.com/releases/2021/12/211222153102.h...

> "Our study found that if you have high cholesterol, high blood pressure, mild obesity and pre-diabetes or diabetes and are hospitalized with COVID-19, you have a one in four chance of developing ARDS, which is significant,"

This article is incredibly misleading. Please don't take it seriously.

First, note the dates: this study is pre-vaccine. You are vaccinated. This doesn't apply to you.

Second, note the wording: if you have X,Y and Z and are hospitalized -- that second part is extremely low probability, even if X,Y and Z are true. In other words, they're conditioning the statement on a rare event to make it sound like it's common for people with diabetes to end up with ARDS. It is not common. It's very rare (but maybe 30% less rare for people with 3+ risk factors.)

To be more specific, read this part carefully:

> Researchers from Tulane University, the Society of Critical Care Medicine and Mayo Clinic followed outcomes for patients hospitalized between mid-Feb. 2020 to mid-Feb. 2021...Researchers compared 5,069 patients (17.5%) with metabolic syndrome with 23,971 control patients (82.5%) without metabolic syndrome. They defined metabolic syndrome as having more than three of the following criteria: obesity, pre-diabetes or diabetes, hypertension and high cholesterol.

> Patients with metabolic syndrome were 36% more likely to develop ARDS, almost 20% more likely to die in the hospital, more than 30% more likely to be admitted to an ICU, and 45% more likely to require mechanical ventilation.

In other words, if you restrict yourself to looking only at the sickest of the sick (i.e. people who are hospitalized; a small sub-population of everyone who gets Covid, strongly skewed toward the elderly), then those with 3+ risk factors are slightly more likely to die than those who do not have 3+ risk factors.

That's all that this study says. The MMWR study I cited more relevant to your situation, if only because you are vaccinated. You are very, very well-protected against severe disease. Even with diabetes.

>my main strategy is to almost never leave my apartment

Wow. I feel lucky to have had a mostly normal social life during the pandemic.

Hypothetically if it ever comes out that Covid was not the killer virus it was made out to be, would you regret wasting 2 years of your life not leaving your apartment? I find it interesting because I know many people who have lived life to the fullest in these past two years that rarely mask, are unvaccinated, and have travelled frequently. None of them became sick in any way. Obviously I know nothing about your age or level of health but I don't think prescribing isolation is the best strategy for the whole society.

This is pretty much meaningless.

An N95, in order to be N95, must filter out 95% of 2.5um particles. For larger particles, this is almost certainly an lower bound as well, but for smaller particles manufacturing techniques and tolerances can produce a wide variety of responses.

Since COVID has been detected in aerosolized droplets well under the micron size, as well as much larger particles in the 5-10um range, we really don't have a ton of information on how this translates to infectiousness for particulate sizes. We don't even have a good understanding of the degree to which infections can spread through tear ducts, which none of these masks address in any significant way. And from an epidemiological perspective, I don't think we'll ever find a signal; behavioral differences between regions is a far larger factor than mask type composition in a population.

That said, I think it is intuitively likely that higher filtration and better fitting masks will generally reduce transmission and infection, but I don't think we have an understanding of what those order of magnitudes are. Studies like this seem especially misleading. And some things are somewhat counter-intuitive; like the way that plastic valves actually seem to make things worse for liquid transmission because of their lack of absorbance even as they are more effective at filtering dry particles.

> larger particles, this is almost certainly an upper bound as well

Shouldn't it be better at filtering larger particles, and therefore a lower bound? Or am I getting confused

Agree that putting numbers like this are misleading.

Yes, I meant lower bound. Corrected.

If N95s weren’t effective wouldn’t more medical pros be catching Covid?

Compared to what? Haven't a lot of them already had covid?

I believe the study mentions many of the issues you just described. Are you saying the article about the study is meaningless or the study itself is meaningless?

I'm not aware of airborne particle size distribution data existing specifically for covid-19 (please share it if you have it), but the majority of particles that might transmit an airborne virus are usually 0.3 microns or greater in size. That is, while some virus particles may linger and those may be smaller than 0.3 microns, the quantity of particles is highly relevant in determining whether someone will get infected - if we can cut a patient's exposure to virus particles by a significant factor, this may indeed prevent infection.

> The count median diameter (CMD) of the cough aerosol particles was fairly similar for all subjects and did not vary significantly during and after illness (p = 0.9340). When the subjects had influenza, the CMDs of all the cough aerosols were between 0.57 and 0.71 μm (average 0.63 μm, SD 0.05), and the geometric standard deviations (GSD) were between 1.54 and 1.83. After the subjects had recovered, the cough aerosol CMDs ranged from 0.57 to 0.89 μm (average 0.63 μm, SD 0.100), and the GSDs were between 1.53 and 2.28. Similar results were seen for the volume median diameters (VMD); the average cough aerosol VMD while ill was 2.44 μm (SD 1.17) and was 2.24 μm (SD 1.50) after recovery. The GSDs ranged from 1.66 to 2.31 while ill and 1.54 to 2.21 after recovery. The difference in VMD while ill and after recovery also was not statistically significant (p = 0.7780).

It is notable that the particle sizes did not differ significantly when the patient was infected with a virus versus the control group. This makes me think that covid-19 is similar.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676262/

This isn't quite correct. An N95 must filter 95% of all tested particle sizes (individually) to be certified. In general these types of filters do best with really small particles and really large particles. There is a size in the middle that in practice is between 0.1um and 0.3um that is called the Most Penetrating Particle Size, i.e. the worst case size, and the N95 must filter 95% of that size. For smaller and larger particles, an N95 will filter better than 95%. For Covid, my understanding is that the infectious particles you're worried about are generally larger than the MPPS and that generally an N95 will filter 99%+ of these.

As was shown in the article, ultimately it becomes all about fit, because even if only 1% of the air is getting around the mask, improving the filter doesn't help that much in overall efficiency.

If you want better than this, you need to go to a higher rated mask with a better face seal like an elastomeric mask with a rubber seal.

Actually, 2.5 micron is the most difficult size to filter. For N95 with an electret layer, filtration is better above and below that size.

I thought N95 and other HEPA filters are not simple sieves? You can't just say anything smaller will be collected less as they rely on different effects of the materials to trap particles:

* https://en.wikipedia.org/wiki/HEPA

I wear FFP2 (n95 equiv I believe) but since I haven’t removed my beard since the start of the pandemic I can’t get a decent fit. So I guess it might protect others from catching my sneezes but I have no illusions that it will do much to protect me.

Having kids at home who go to schools where neither teachers nor students have worn masks since the start of the pandemic also makes the idea of wearing a mask to the grocery store once a week feel pretty useless anyway.

The key quote from the study:

"To calculate exposure and infection risk, we use a comprehensive database on respiratory particle size distribution; exhalation flow physics; leakage from face masks of various types and fits measured on human subjects; consideration of ambient particle shrinkage due to evaporation; and rehydration, inhalability, and deposition in the susceptible airways. "

My wife and I, plus my side of the family, skipped cloth masks altogether. We managed to acquire a load of KF94 (Korean N95 equivalent) from friends and relatives in Korea and used them (and continue to use them). Neither my parents (dad is early 70s, mom is late 60s) nor my wife and I have gotten covid yet*

On the other hand, my wife's side of the family quickly abandoned use of the KF94s and switched to cloth masks. All of them got covid in late 2020, and all of them just got omicron again.

Everyone in both sides of the family got vaccinated plus boosters.

* While obviously not 100% certain, we got tested frequently both using in-home antigen kits and PCR. I was probably the most at risk due to having changed jobs in early 2021 where everyone was told to come back to the office. However my employer provided free daily PCR testing, which I took advantage of. Have had 100% negative daily results thus far...

Are those masks better for people with glasses? I have to wear a mask in public transportation and at work, and I always get fog on my glasses. This sounds like a small thing, but having to adjust how you breathe all day just to be able to see properly is tedious and tiring.

Glasses person here: yes. Way less fogging.

Can confirm they are much better for glasses than surgical masks, the air that does leave goes downwards and outwards from the mask far more than up to the eyes.

Yes and it's actually a sensitive test for fit. If you get fog then air is leaking out unfiltered, so when you breathe in, it's also not filtering that part.

It's imperfect bc you can have gaps around your chin which won't fog up. But it's one of the nice parts of the good filtered masks. And in the winter it helps keep the bite of cold away

No. But it’s still worth buying a 10-pack and see whether it solves some of your problems, because in the worst case, you still have 9 masks which will actually protect you from the virus.

I've bought a pack of N95 couple of days ago. Glasses are a major first problem. When I exhale most of the air goes out above straight into the glasses. With the cold temperature outside it's problematic to see. But IMO this proves the point that N95 masks are mush better. It slightly collapses when I inhale and most of the air goes through it, the fit is good. While for ordinary masks the air goes freely through the sides. Ordinary masks protect others from large droplets, but small droplets or aerosol go freely with the air. N95s become quite wet inside quite quickly for that reason.

So air still escapes out the top and they quickly get gross and wet. Great salesperson, where do I sign up?

This would made sense for Delta and the initial strains but ya’ll look a bit neurotic wearing N95 for omnicron unless you are already near death. It’s so damn contagious, when do we accept the fact that this isn’t going away and we cannot possibly wear masks forever?

It escapes during exhale since it naturally pushes the mask away and the fit becomes looser. During inhale air pushes the mask toward the face and the fit becomes tighter.

Most problems are during some, even light such as walking, physical activity when more air is needed. Inhaling is limited by the mask, but it cannot hold a strong exhale. I imagine sitting in a subway or a train should be fine. Hope to get on a train trip in 2 weeks so I would rather postpone my second covid, that's why I'm going for those inconveniences.

did you pinch the wire to conform it to the bridge of your nose?

If fitted properly the fogging should not be an issue. That can be difficult to maintain on some people's faces though. Using a headband style instead of ear loops can make a big difference for a tight fit. Some medical users will use a little bit of bandage tape to seal up the top, which may be a little difficult to keep up with for average users, but may also help remind people that masks don't work very well when you're constantly taking them on and off. If you're in a place with potential clouds of aerosols floating around, the mask should stay on the whole time.

That’s a cool stat, but whatever…Just traveled (USA) via airplane. When I arrived at the airport, people were sneezing and coughing everywhere. On the plane, same thing. I’m my Uber, same thing with the driver. I tested positive after all this, albeit with mild symptoms. Seems everyone has it. Also seems like no one cares anymore (at least all these people). If Covid was a more serious issue, we’d all be doomed. Doesn’t seem USA govt thinks this is a big deal because otherwise they’d shut everything down. Know why there are no flight attendants and flights canceled, because everyone on planes is spreading it. And now the quarantine days has been reduced. Carry on people…

> If Covid was a more serious issue, we’d all be doomed.

Or maybe people stopped caring because they realized that it's not a serious issue?

Here is what I think (US-centric):

- Most people are tired of masks and even if they use them, they are neither wearing them nor cleaning them adequately

- Vaccination/boosters are the only reliable defense for the average person

- In 3 years or less, people will wonder what all the fuss was about and simply will treat COVID-19 like a common cold. Your management and colleagues will expect you to show up for work, COVID or not.

I'm not justifying this behavior. Just stating what I think we'll see in the future.

This is right. Whether masks work or don’t is irrelevant. The policy failed.

If an individual wants to not get Covid, the only solutions are vaccination and distancing.

At this point with Omicron, it's also that the messaging has gotten so damn muddy and contradicting. Here's what I mean.

* Get vaccinated to protect yourself. Well now we know you can get a breakthrough infection.

* Get vaccinated to protect others. Well now we know you can still infect while vaccinated.

* Wear a mask to protect yourself. Well now we know that masks don't really do a damn thing unless you wear an N95 properly, even then it's not super effective against Omicron.

* Wear a mask to protect others. Again, we now know that masks do little to protect others with this variant.

The frustration in all of this is, as a young and healthy person, I'm not worried about COVID. And if there is nothing I can do to protect others, please just let me sign the liability waver already. If I get sick and die, that's on me, just please stop enforcing mandates "for my own good".

Just because something is not 100% effective does not mean that it should be abandoned entirely. All of the measures you mentioned still have some degree of efficacy.

The fact that breakthrough infections sometimes occur is not a valid counterargument against vaccination.

People have moved on precisely because it's not that big of a deal. It's over thankfully. Time to move on.

"The Centers for Disease Control and Prevention is considering updating its mask guidance to recommend that people opt for the highly protective N95 or KN95 masks worn by health-care personnel, if they can do so consistently, said an official close to the deliberations who was not authorized to speak publicly."

CDC weighs recommending better masks against omicron variant, Washington Post, Monday, https://www.washingtonpost.com/health/2022/01/10/cdc-weighs-....

The point of masks is not necessarily protecting the wearer from other people but other people from the wearer of the mask. It's kind of an unselfish and considerate thing to be wearing a mask: you might be infected without knowing and exposing others around you. A mask reduces that risk.

If everybody wears a mask, you effectively have two layers of protection. A potentially infected person wearing a mask would mostly not be spreading the virus very effectively. Their mask would catch most of their droplets. Your own mask then reduces the risk further. If either of you doesn't wear a mask, the risk is much higher. If nobody wears a mask, higher still. It's not rocket science.

> It will take 25 hours for an infectious dose of COVID-19 to transmit between people wearing non-fit-tested N95 respirators

Is this backed up by _any_ real world data? Because this seems to be overly optimistic, judging from the way Omicron has been spreading.

Most spread, including omicron, is small (unmasked) friends-and-family gatherings. NY did contact tracing to find that. Those are extended, in-door gatherings without masks and with close proximity.

I don't think omicron's spread says /anything/ about the efficacy of masks.

How many people are wearing N95s? I don't think I've ever seen one in the wild, only KN95 and that's still relatively uncommon. Most people are still going into social settings with no masks, so that's a more obvious reason for the spread.

KF94 masks have been a good trade-off between protection and comfort. They don't filter to the same degree as N95, but they are a hell of a lot more comfortable to wear, and therefore more likely to be worn consistently.

I've tried KF94 and KN95 and find them more comfortable than N95 too. I've also noticed differences in brands. Some brands have more comfortable brands than others and that makes them easier to wear.

Yes sure N95s are better but they are so hard to keep on for long time for me since I wear glasses. I finally found a comfortable one made by Aegle, I think, but they seem to be out of stock everywhere.

75x, ignoring everything else, that is.

However, we don't live in a perfectly sterile world, so that number is probably going to be a lot lower in practice. A pity that they didn't measure that.

It’s still useful if it is “only” 25x better or even just 4x.

Could be, but you have to take practicality into account. What if people use the same face mask several times a day, touching its surface every time they put it on? Even many government officials do this. Is it reasonable to ask people to use a stricter procedure and pay for their own face masks? Considerations like that ultimately determine the effectiveness of a measure.

My gripe with mask mandates is this. Those cloth masks do almost nothing. The holes in cloth are like a gaping barn door to a virus. Same goes with those bandana over the nose masks. Cheap surgical masks are a bit better but not great.

I guess the goal was to do something rather than nothing, but unless you are at least using a medical grade mask you're not accomplishing very much.

It's like mandating seatbelts but not specifying type so a shoestring tied across your chest is considered a seatbelt.

> I guess the goal was to do something rather than nothing

The appearance of not doing nothing has driven every recommendation/mandate/edict during the past 2+ years.

I believe that while cloth masks are not very effective at protecting you, they are a LOT better at reducing viral spread if you are the infected party. So it still can be quite effective at reducing overall spread of Covid.

That being said, if you want to better protect yourself, you should probably be wearing a better quality mask. It's the reason why I've only ever worn KN95 or N95 masks since the start of the pandemic.

What is that based on?

Cloth masks satisfy those policing people to wear a mask. For me, that's 100% effective.

The original guidance IIRC is to both wear masks and maintain social distance. My interpretation of this was that if you are wearing a mask, not only are you filtering the air you take in, but also out, and even with a cloth mask, you are at the very least reducing the radius of what you are shedding vs being unmasked and talking out loud.

To me this was all null and void if you are sharing a tight enclosed space for any significant period of time- like a restaurant, or even an office. Then you need something like an N95 to get any significant protection.

I understand people's frustration, but I think its important to remember that organizations like the CDC are trying to make a recommendation that balances many factors like convenience/discomfort vs availability of masks, vs what is actually understood about the transmissibility of the virus in its ever changing forms. Even taking that into account, it seems relatively simple to set up experiments that can test the effectiveness of these claims- and why no one has done this is kind of baffling to me- I am guessing these are prevented by ethics concerns where you will have to expose healthy people to the virus.

The main benefit is probably forcing you to deal with sneezing, coughing, and touching that area of your face...protecting others.

I, for one, cannot understand people NOT wearing N95/FFP2 masks or at least similarly-shaped masks made of other materials. ;-)

The standard surgical masks totally kill my nose. I understand that every face is different. For me, they are just that much more comfortable. And with other people not wearing their masks properly (or sometimes not at all, because some glass panel is clearly stopping the aerosol spread!), I’d rather have better protection anyway.

I visited British Columbia a few weeks ago, coming from Europe, and was almost shocked to see that inside stores, etc., some people _still_ don't wear any masks, others wear them just covering their mouth but not nose (which I also count as "not wearing a mask"), and most people that do wear masks (properly) use simple cloth masks.

Over here in central Europe, FFP2/N95 masks have been mandatory in such settings for a long, long time now.

Interesting that Europe as a whole has fared worse across basically the whole pandemic vs. Canada: https://ourworldindata.org/explorers/coronavirus-data-explor...

Canada reached a very high percentage of vaccination across the whole population, and rather quickly compared to other nations.

Why hasn't the market responded to demand for N95s? It's been almost 2yrs now and we're all still stuck using those blue surgical masks (which are mandatory in hospitals here in Ontaro, Canada) or whatever random stuff people buy, at best K95.

Are there some grueling regulatory rules in place or has no just bothered?

They just be getting pushed for mass production like the vaccines.

There's something broken about this market, not sure what's going on.

https://www.nytimes.com/2021/02/10/health/covid-masks-china-...

There are 20 packs of N95 respirators sitting on the shelves at most Home Depots here in the US.

I live in Colombia where N95s are impossible for non-medics to get. But I can very cheaply (like 0.10 USD a piece) mail-order sticky metal pieces that vastly improve the fit of the masks I do use. They last basically until washed. Highly recommended.

I have been wearing a FFP3 mask for 18 months, which costs $10.

I have washed it 2 times, but it can handle 50 washings.

Apparently it's a much better mask, it has copper in it.

Although I had to replace the tiny metal wire in it since it broke, to make sure it was air tight.

I switched from an n95 to surgical masks after a month the reason being they are cheap enough to throw away. Also government forbade them in public transport. Even if they do allow it I don't think I'll go back.

Forbade N95 in public transportation? Why is that?

I wonder in how far the effect is diminished by reusing those masks. I read somewhere, that they lose a lot of their protection after getting damp from wearing.

These masks are usually single use, but people use them over weeks or more.

Does this hold true for people with beards?

Yes, if they shave

Even if they don’t, the n95 will filter better than whatever lower-grade mask they were otherwise wearing.

yes, but if it's not forming a tight seal it might not be filtering enough to matter

Will it? If your beard prevents a seal you're just going to be sucking in air from through the sides like you would with a standard mask, no?

some will go through the mask (and be filtered).

Kinda like adding a 100kohm resistor in parallel with a 10k ohm. Most current will go through the 10k, but there will still be some going through the 100k ohm.

Short answer: N95s are not as good if you have a beard, but they are still better than cloth. See https://pubmed.ncbi.nlm.nih.gov/34006963/ for details.

So much anti-mask rhetoric here.

No mask < cloth mask < surgical mask < N95 etc < P99 etc

None of these are 100%. Does not mean they’re 0% effective.

When I cant get an entire Pizza but I can get 2 slices I don’t say ah fuck it, I’ll have none at all.

Edit: if masks weren’t working at all, we’d see a lot of medical professionals catching covid. A lot lot more than we see now.

The "anti-mask rhetoric" is not about the effectiveness of masks, but the necessity of mandating them.

As for me, I've been living quite happily without one since about July last year.

Must be nice being a healthy individual who doesn't care about spreading covid to less healthy people.

Terribly sorry about that. Perhaps if they have serious health concerns, they should take preventative measures such as being vaccinated, wearing masks, or isolating.

But as far as the people I work with every day, who also do not wear masks, I have not spread COVID to any of them. Nor my family, nor my volunteer groups.

Masks exist to reduce spread. You're the one who has to wear them for it to be effective at reducing spread.

This is the stupidest take.

The difference is clear between states that require masks everywhere and states that don’t. Masks have no effect if they are mandated or not. My state has had every single new wave occur while already mandating masks.

A lot of people only want to think about it on their individual level, instead of realizing that every measure like masks, even lower quality masks, slows the spread on average and prevents the waves of infections from being as sharp or as massive, which really matters in terms of hospital capacity and general economic disruption caused by simultaneous sickenings. But it's probably preaching to the choir at this point about large segments of society being essentially selfish and myopic.

The “selfish and myopic” people I know in states that don’t have mask mandates have happy kids who go to school and can look at each other’s faces and grow as humans.

Here in NYC we have woman yelling at kids to keep their masks on and they are in and out of school on a whim.

Who is being selfish and myopic?

It seems to me rather more selfish and myopic to shut down all of society over one's personal fear of the sniffles.

Calling covid "the sniffles" doesn't make you sound reasonable.

That’s what it is for almost all children

Yes, but HN isn’t made up of children. The vast majority of people here are adults, a population in which Covid-19 is a risk for a large proportion. People aren’t talking about children and saying “you’re afraid of the sniffles* (* is only sniffles for children)” is disingenuous.

HN is comprised of tech workers, who dramatically skew younger and vaccinated. These are people for whom covid is very much just the sniffles.

The classic sniffles that kills millions a year that we all know and love, right

If I were playing a video game and there was some armor which gave me even 10% protection, I'd put it on.

If you were playing a video game you would also sprint all the time, rather than walk. Do you sprint all the time in real life? The difference is that in real life, sprinting has some non-negligible cost (eg. due to discomfort), whereas in a video game all you have to do is hold down a button. The same applies to masks/video game armor. Putting on a mask requires you to endure a non-negligible amount of discomfort for the entire time you wear it, whereas putting on an armor in a game causes you none.

> The same applies to masks/video game armor. Putting on a mask requires you to endure a non-negligible amount of discomfort for the entire time you wear it, whereas putting on an armor in a game causes you none.

This isn't really true, plenty of games make your character slower / heavier depending on what you have equipped.

I'd also say that, for me, a mask is really not that uncomfortable and the discomfort is negligible.

>for me, a mask is really not that uncomfortable and the discomfort is negligible.

Great, so wear one. Nobody is asking you not to. I think its fairly uncomfortable and makes interactions harder. I won't.

I would too. But then again then is zero discomfort wearing in-game armor, and you can change it in a second if it had downsides like making you hungry faster.

Yeah, I, too, tend to drift towards Minimax/Maximin strategies when playing games. Basically, I know I'm there as soon as all the joy is sucked out of my play. That's why IRL it is not an option at all for me.

I'd strongly encourage you to look into your mask hierarchy. Cloth and surgical masks are not particularly evidence based devices. Even N95s have a lot of pseudoscience supporting their use (minimal size of viruses). They probably do something -- but go around in a well fitting N95 mask and an active lifestyle and you'll see that it's simply infeasible.

Your commentary about medical professionals is bizarre -- of course fewer medical professionals catch covid. They are exposed to it nearly constantly and generally have functional immune systems. If you work in a hospital, something you'll notice is you just stop getting sick very much.

Everything is a game of tradeoffs. Cloth masks in particular are obviously not worth the tradeoffs. Surgical masks are likely not. Maybe N95 are in particular situations.

So your point is medical professionals don’t fall sick primarily due to their immune system?

Don’t you think this has to do with their personal protection equipment and routine of washing hands etc?

Someone on HN just bought and tested a ton of masks, including surgical masks. Surgical mask material does filter nearly as well as N95 mask material, and the difference is fit. Based on data reported by this guy with actual equipment to test masks, most of your assumptions are highly questionable.

https://news.ycombinator.com/item?id=29878971 https://news.ycombinator.com/item?id=29888381 https://news.ycombinator.com/item?id=29892032

Surgical masks are more fluid resistant than N95 masks, which is why they are used in hospital settings (the goal is to note contaminate the patients, not really about self protection that the N95 is better at). They are designed to solve different problems.

Go read the links I posted. You're just regurgitating whatever sounded plausible to you ages ago and has now become "knowledge" to you.

That poster literally measured particle filtration efficiency (PFE) as the mask exists on his face.

The data, summarized for the lazy:

- Surgical mask worn normally: 79% PFE

- Surgical mask with an ear saver: 91% PFE

- Surgical mask with a brace: 98% PFE

- N95, worst fit: 80% PFE

- N95, best fit: 99% PFE

The links you posted... from a mask salesman.

PFE isn’t the measure you want: you need to know what amount of 13 micron particles are blocked by the mask in human conditions.

> You're just regurgitating whatever sounded plausible to you ages ago and has now become "knowledge" to you.

This isn't rocket science, see:

https://www.cdc.gov/niosh/npptl/pdfs/UnderstandingDifference...

Surgical masks: Fluid resistant and provides the wearer protection against large droplets, splashes, or sprays of bodily or other hazardous fluids. Protects the patient from the wearer’s respiratory emissions. Does NOT provide the wearer with a reliable level of protection from inhaling smaller airborne particles and is not considered respiratory protection

N95 masks: Reduces wearer’s exposure to particles including small particle aerosols and large droplets (only non-oil aerosols). Filters out at least 95% of airborne particles including large and small particles.

The masks have and have always had completely different purposes. The fact that we are using both during this pandemic to protect against COVID not withstanding. Now, people are using surgical masks in novel new ways (with braces and such to try and retrofit a seal on them), but they were never intended for that.

Relevant to the comments about fluid resistance: the difference between 3m's medical N95 respirators and construction N95 respirators is often nothing more than color, being stamped with a lot #, and additional fluid resistance. For example, the 1860 vs 8210. [0]

Medical personnel using the construction respirators out of necessity can wear a surgical mask over them, it's something I've seen locally. (I don't know whether that's a practice that predates COVID 19)

[0] http://docplayer.net/203020246-N95-tool-kit-algorithms-and-c...

Many, many people choose to reason only in binary terms.

Or to deny reason at all; maybe call it "unary" logic?

-----

"Everybody has to die sometime."

"If it's my time to go, it's my time to go."

"I could get killed crossing the street."

-----

Total denials of the possibility that anything has a cause.

> if masks weren’t working at all, we’d see a lot of medical professionals catching covid. A lot lot more than we see now.

Post hoc, ergo propter hoc.

"I am carrying my anti-tiger rock. I have not encountered any tigers today. Therfore, my anti-tiger rock is working."

You realize that medical professionals are almost universally vaccinated, have in large number had the virus already, and take other precautions, right?

Whilst you have a good point for the present, it is noteworthy that medical professionals working in covid wards (and so the ones with FFP2/equivalent or better) had, in the studies I have read, consistently lower rates of infection than even other hospital workers (with only surgical masks) during the first wave.

I recall seeing studies from the UK and US showing this, and possibly other countries.

There’s no question they do something. The question is whether in practical terms they’re worth mandating society-wide. It reminds me of the old 55mph speed limit. Sure, properly enforced it would lower oil usage and save lives. But it wasn’t properly enforced and in practice became a random tax on those who got pulled over.

Not all interventions are effective when mandated society-wide.

I think a lot of anti-mask discussion is really just people love and absolutely cannot resist pointing out that someone else is "wrong" in their judgement. When that someone else is an expert, especially so. HN users are probably even more prone to this behavior (pointless pedantry seems more common in nerds).

Literally yesterday we had someone with a $250k test rig test dozens of masks: https://news.ycombinator.com/item?id=29878971 He also commented on how fit affects mask performance in great detail: https://news.ycombinator.com/item?id=29888381, https://news.ycombinator.com/item?id=29892032 In particular, he finds that a properly fitted N95 filters 99%+ of particles. A 75x boost in Covid protection seems reasonable in that case.

>None of these are 100%. Does not mean they’re 0% effective.

Life is about cost-benefits. I'm not going to bother with a 11% effective mask if I'm vaccinated.

And CDC recommends not using N95 masks so health care workers can get them. So... What should we do?

Source on that?, CDC already recommends using N95 for Omicron and is widely available.

https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-si...

> DO NOT choose masks that > Are specially labeled “surgical” N95 respirators, as those should be prioritized for healthcare personnel

I can't imagine the negative environmental impact if everyone used disposable masks.

Why would the impact be larger than people reading newspapers, or using disposable napkins/serviettes/tissues? It almost surely is small compared to transport, fashion, agriculture, etc.

p100 all the way. They don't last as long, look freakish and are hard to breathe through. BUT! If you are around a TON of people for 20 minutes it works perfect. We have family that do surgeries p100 all the way.

Anyone recommend a trustworthy place to buy N95 or KN95 masks online?

https://www.projectn95.org/ seems to have good recommendations.

I don't get why this is something Axios is raising, they're a corporate, partisan trade rag that frames public health as a political issue. The medium is the message.

More mask -> Less social interaction -> More media attention -> More fear -> More mask...

I’ve found the opposite to be the case. Masks facilitate increased social interaction as people can more safely meet each other indoors or share a car-ride – which is important when less daylight and colder/wetter weather limit outdoor socialising.

The media are more interested in what’s new and in my country (Ireland) masks have been old news for well over a year.

Since masks mean less interaction (contrary to what you wrote) people are looking to fill part of that information void through mainstream media. Which is a fear machine at the moment. More fear -> More masking up

Nobody said media is talking about masks all day.

We are at the point that the damage is visible on children so I don't care about bowing to HN's liberal readers anymore. It is clear as daylight, mask mandates are damaging our society.

With all the talk about seal tightness I'm deeply surprised so few people use a fitter to tighten their masks.

I feel naked without my fitter - I'd feel the air leaking from where it's not supposed to.

What is the role of face masks, however effective, in a world where a variant of Covid-19 is endemic? Sooner or later we're going to catch it much as we catch influenza which year in year out, kills up to an estimated 650,000 people every year.

Fake News. Here is the real-world study. It is pre-covid and without pro-covid bias: https://www.sciencedaily.com/releases/2019/09/190903134732.h...

Thanks for the interesting counter-evidence. I’ve upvoted your comment but I suspect it would have attracted less downvotes if you omitted the blithe “Fake News” dismissal of the featured article.

Pandemic is over, I hope we can now gather all the real world data on how we dealt with it and see which one was effective and which one was profit driven.

How is the pandemic over?

I think OP omitted "When the" from their comment.

I think they said exactly what they meant.

I think possibly they meant it's endemic now. Most officials don't want to call it that yet, but I think it's pretty well accepted that at some point, we're going to call the pandemic over not because covid is gone, but because it's just everywhere all the time.

...and are still pointless after n minutes in setting y without ventilation.

Please lets just move on from mandate nonsense that clearly 2 years in is not working.

I know this will get downvoted with a load of 'flatten the curve' style rhetoric. But seriously, you're pretending the combined economies of the west can't come up with a better solution and yet you want to start taking the species to space? Gimme a break, were better off confined to this speck of dust if this is the nonsense we're dealing with...

? What is your control group for claiming that masks don’t work? Florida?

seriously, 2 years in with 90%+ of the population vaccinated and mandatory masks and Omicron spreads like wildfire in the UK and you are claiming a) the vaccines stop the spread or b) that masks work. are you ignoring reality or somehow going to blame the <10% who are probably also working from home...

I didn’t claim any of that at all with my five word sentence.

But I would certainly claim that vaccines and masks are doing more than zero to help, the studies and science are openly accessible.

Even if vaccines and masks just helped stop 10% of infections it’s a gain.

What’s your improved proposal to stop an aerosol-borne virus with that kind of R0-value in places you can’t exchange air effectively?

I’ll give you a hint: they don’t have one. they just want to complain.

Kind of shocking to see objectivity normally flexed by HN thrown out the window as soon as the subject of masks comes up.

Improved ventilation as manditory, targeted vaccines, isolation for at risk groups. Careful proper monitoring for at risk groups combined with low grade random monitoring of the wider population.

Importantly EDUCATION around basic h&s and personal sanitation and not to be a mouth breather on public transport...

Masks as normal in treatment and hospital settings and frankly a working economy which focussed on increasing treatment capacity and preventative measures, aka building and installing air filters en-masse

It's not exclusively about R number is about saving lives.

80%++ of cases are far from fatal and probably 95%++ are akin to a flu like response from a healthy person. Again borne by case numbers even pre vaccine in the UK.

It's not about moaning, it's about trying to educate people in statistics, science and personal responsibility, not group think and politics.

Unfortunately staying at home forever does more than zero. But that's just not a reasonable option.

Not to repeat this as infinitum but R0 is a useful number to inform. It's not something you should be seeking to directly change.

Killing cities of people to contain outbreaks achieve a lower R0, but frankly at this stage we're so far off topic of mask efficacy or reliability.

There are always going to be leaks and there will never be 100% protection and there will never be "zero covid". The entire mask argument is irrelevant and only serves to distract and divide. We should have said from the very beginning that people should stay home if they don't want to catch the virus. And if you want to go out, it's at your own risk. It was that simple. Instead we have tripped over ourselves for 2 years trying to come up with ways to curb the virus without having any impact whatsoever, destroying and dividing the fabric of our society along the way.

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