The science of mask-wearing hasn’t changed, so why have our expectations? | Hacker News Reader

The science of mask-wearing hasn’t changed, so why have our expectations?

fivethirtyeight.com

107 pointshooloovoo_zoo283 comments

What confuses me is why so much scrutiny is being placed on the practice of wearing a mask. It just hardly seems like much of an inconvenience. And common sense dictates pretty convincingly that it must have some benefit, however small. So then why so much effort into deciding if it works or not?

I suppose there are two answers to that question. One, health officials want to know if masks give a false sense of security so they can spend their time promoting measures that will actually make a difference. Two, folks just want a reason to avoid the minor inconvenience or, worse, have been led to believe that mask mandates seriously impinge upon their rights. My concern is that the most common answer is the second and articles like this only serve to confuse people at a time when we need to accept that we must make small sacrifices to solve this problem.

Just in response to your comment "It just hardly seems like much of an inconvenience.":

I suspect that means you are not out of shape or live in a hot humid place. I wear a mask on those very few occasions when I leave my home but it takes a while to acclimate to it each time and often when I take it off my face is wet. And don't even get me started on the pain of wearing both a mask and glasses in a humid environment. Is it a valid excuse for not wearing one? No it isn't.

Edit: logic correction, I think...

Edit 2: I proofread poorly.

I'm in Fl. When I walk out of a grocery store my glasses fog up. Is that a big enough inconvenience to ask them to turn off the AC? Nah...

My glasses don't fog up nearly so much as that by simply wearing a mask; little bit on some exhales. So, given the benefits to others, I'm okay with it.

>So then why so much effort into deciding if it works or not?

FUD around masks and their effectiveness is being deliberately spread by people and groups with a political agenda, primarily through disinformation campaigns on social media. This isn't an entirely organic phenomenon.

Even the CDC was against mask use by the general public at first, so while much of the naysaying is now political, there was also seemingly legitimate information being pushed by prominent organizations that encouraged people to ignore masks.

Also, there's no character limit here, you can write the entire phrase instead of using obscure acronyms.

>Also, there's no character limit here, you can write the entire phrase instead of using obscure acronyms.

FUD is no more an obscure acronym than CDC. FFS this is a programming and tech forum, people throw acronyms around all the time.

...the CDC was against mask use by the general public at first

And they too admitted to spreading FUD about masks, in the misguided belief that stopping average people from using masks would leave more masks for the health care providers.

That should reinforce the important point that we're dealing with unqualified, clown-show/amateur-hour political appointees in multiple levels of government, making critical decisions, at this point, a point in time, unlike most points, where leadership or it's lack matters.

And I know that FUD is just a long-standing acronym for "fear, uncertainty and doubt" and I too could just write that. But being so long-standing, the term not is only convenient but has come mean a particular kind of fear, uncertainty and doubt, that spread through a particular of public relations system.

It's not clownish, just the opposite.

There was a severe shortage of N95's at the time, and if the public thought masks were important, there would have been an unprecedented run on PPE and the medical community would have had squat. Given that masks, particularly N95s are actually effective in a Healthcare environment ... it was the exactly the right call to make.

Get the masks to those who it will actually help, not the public for whom it will make a smaller difference.

Once production is ramped, or we have enough PPE, then it makes sense to have a pro-mask policy for the public.

From a communications perspective, it's obviously problematic, but in terms of equipment triage, it's highly rational and we actually want our leaders making these kinds of tough decisions.

The WHO and various governments should have been more efficient in their messaging however.

Yeah this is the part of the issue that my social media feed seems to attach to. They post comments from politicians and public figures (and medial professionals) saying early on that we shouldn't wear masks.

I'm sad that the original messages didn't come across as the nuanced issue that it is. Hospitals need the N95 stuff because they are exposed at high rates for a long time. Hospitals also educate their staff on proper protocol when wearing a mask so that people don't negate the effectiveness by wearing it wrong or touching their face after removing it.

The public isn't educated on proper mask wearing procedure. We don't know how to test that a mask fits properly. We don't have the same training to avoid cross contamination and poor mask hygiene. We don't understand the marginal benefits of masks and how it creates a false sense of security causing us to take more risks and spread the disease more quickly.

So at first, it makes perfect sense to funnel the best masks to the highest risk people and encourage "stay at home" (instead of "go outside with a mask") because it limits disease spread the most and protects the community.

I'm sad that it has turned in to "but they said masks did nothing" as an excuse to not wear them. It was never that they did nothing, it's that masks ALONE is not enough. Masks and proper behavior are necessary together.

> I'm sad that it has turned in to "but they said masks did nothing" as an excuse to not wear them. It was never that they did nothing, it's that masks ALONE is not enough. Masks and proper behavior are necessary together.

If you have the correct behaviour (hand washing, distancing) the mask provides you no benefit.

The only point to wearing a mask is if you are unable to maintain that distance, or you're stuck in a room with symptomatic people. But if you're doing that you're also provided with eye protection and gloves and a gown and copious water for handwashing, and you've probably been trained to don and doff the PPE correctly, and maybe you even have a person acting as a PPE spotter helping you put it on or take it off correctly.

No one is telling people to wear masks in their own house or sparse outdoor spaces, and in most cases there are no rules about outdoor spaces at all. Where the anti-maskers are causing a problem is refusing to wear masks indoors. Airflow can be very different in different buildings and the "6 feet apart" distancing rule is fairly arbitrary. It is implausible to actually properly distance in most indoor spaces. Hence masks are indeed important, even for those following the other "rules".

That aside, there is high overlap these days between people that say masks don't work and people that are completely negligent about distancing. It is a little ironic, as there were concerns that belief in masks would make people distance less due to sense of security.

I don't recall the exact CDC statement but I do recall quite a few of my (well educated, liberal, in some cases educated in public health) friends posting on Facebook that masks actually do more harm than good because "people touch their face more" or something. I remember thinking a lot of the messaging seemed wrong, but I also wasn't confident enough about it to start getting into social media fights about whether people should wear masks.

So there definitely was some narrative going around back in March that masks had an actively negative effect for an individual, not just that masks do nothing. That said, anyone who is an anti-masker at this point is being ridiculous.

> if the public thought masks were important, there would have been an unprecedented run on PPE and the medical community would have had squat

This still happened, though. All the stores that sold masks to consumers sold out, very rapidly, at the same time the Surgeon General was tweeting that they didn't work.

They should've ordered they be pulled from sale, not lied about their efficacy.

This is also incidentally the exact sort of thing the Defense Production Act is actually for. It could be invoked, used to give guaranteed quantity and price contracts to suppliers and avert the entire issue of supply runs.

Which likely wouldn't happen because it's not like someone who gets a profitable contract from the Federal government, retools their factory, isn't going to then try and squeeze as much production out of that as they can anyway.

> it was the exactly the right call to make.

Lying is never a defensible policy. If there was reasonable concern about run on PPE, then perhaps government order restricting or banning their sale to general population (like it was done by some governments) should be considered.

Lying is absolutely a defensible strategy when done for the greater good.

That doesn’t mean that there hasn’t been a ton of clowny behavior from leadership.

It destroys public trust. What do you now say to people who refuse to wear masks? Do you say "I was lying to you earlier for the greater good, but now I'm not." Why should they ever listen to you again? You could be lying again.

This is exactly what was done here in Czech Republic - sale of high grade PPE to public was banned, massive PPE shipments ordered and home made masks made mandatory everywhere.

This seems to have been effective, as most of the restrictions have been lifted and we are back to sporadic local clusters by now.

"There was a severe shortage of N95's at the time, and if the public thought masks were important, there would have been an unprecedented run on PPE and the medical community would have had squat."

Uh, you what actually happened? There was been an unprecedented run on PPE and the medical community got squat. It's bizarre to have to recite headline news from two months ago ... doctors in NYC using garbage bags instead of real protection. Hand sanitizer unavailable. Nurses in hospital prohibited from using their own masks and not getting them from the hospitals. The Federal government hoarding PPEs for who knows what asinine reason.

Well I think you helped to prove my point.

As I said, there was excess demand for PPE, but by and large, most medical staff did have access.

That there were some doctors who were unable, means that obviously there was some shortage.

But Dr. Fauci and the WHO had of indicated that 'every American should wear a mask' - then all doctors would have been wearing garbage bags through the entire affair.

The 'excess demand' from natural concern was bad enough, but 350 Million Americans clamouring for N95's would have wiped out any hope of keeping the medical staff in place.

It was a rational decision given the risks and unknowns: We need to get PPE to doctors because the value to the general public is limited.

A tough and difficult decision at the time, but they did the right thing.

The claim here is that 1) CDC knew masks were effective but 2) decided to ignore that to preserve stocks.

For you to support claim 1 all you need to do is post links to the meta-analyses or randomised control trials that show the effectiveness of masks to prevent the spread of respiratory disease. There are lots of RCTs around mask wearing to prevent the spread of respiratory disease.

> And they too admitted to spreading FUD about masks

No they didn't. They haven't even changed their advice. Now they say "it may prevent the spread", they definitely don't say "it does prevent the spread", and they're still trying to preserve stocks of medical supplies.

I wish they had treated the public like adults:

"Listen, we believe masks are effective but we don't have enough for medical personnel who need them right now so unless you absolutely need one please stay home, stay safe, and leave them to doctors, nurses, and other emergency personnel."

No misinformation and the vast majority of people would have complied.

Lying to everyone just cost them credibility and probably lives when this is all said and done.

"And, by the way, there is plenty of toilet paper." I bet that would have stopped the panic buying, too.

Always this talking point whenever anyone suggests they should tell the truth. What else should they lie to us about because the public supposedly won't react well?

It's a self-fulfilling prophecy. The more the state lies, the less we listen to it, and the more we start looking out for ourselves, and disregarding the public good.

Government officials see us behaving like this, they assume we're too dumb and self-centered to do the right thing, so they attempt to manipulate us in order to get us to behave properly.

I don't think the public would've acted like adults though, but I don't think it would've changed anything either. Even with them saying that masks don't work, there was a mask shortage almost everywhere.

Then the worst case: Still a shortage and no misinformation (aka lying) to undo.

Still a major win over our current situation.

But the shortage would have been worse ...

How does a shortage get worse than "we're all out"?

The duration can differ. A shortage lasting a week is better than a shortage lasting months.

> That should reinforce the important point that we're dealing with unqualified, clown-show/amateur-hour political appointees in multiple levels of government

In light of this point, how much would you trust a vaccine approved by the FDA or CDC?

I’ll wait until it’s approved by reputable non-US health care agencies. Especially if a vaccine magically arrives before November 3rd.

> Even the CDC was against mask use by the general public at first,

It. Was. Not. The WHO and CDC both issued guidance that public use of personal protective equipment was a bad idea, for fundamental scarcity reasons. And in both cases the messaging was done poorly in a few spots and could have been interpreted as statement that masks don't work against covid. They were heavily criticized for this at the time, and the criticism was carried by the media. No expert ever told people that masks don't work, or that the public shouldn't wear them. They were telling people to save them for the health care workers!

And getting to the point upthread: that bit of misinformation is, again, something being deliberately propagated by people with a political agenda.

Perhaps I’m just dense, but that’s exactly how I would read this tweet from late February: https://mobile.twitter.com/cdcgov/status/1233134710638825473...

“ CDC does not currently recommend the use of facemasks to help prevent novel #coronavirus. Take everyday preventive actions, like staying home when you are sick and washing hands with soap and water, to help slow the spread of respiratory illness. ”

The US Surgeon General, in late February:

> Seriously people- STOP BUYING MASKS! They are NOT effective in preventing general public from catching #Coronavirus...

https://twitter.com/surgeon_general/status/12337257852839321...

It's not surprising people got "masks don't work" from that messaging.

You left off the second half of that tweet in your quote:

> but if healthcare providers can’t get them to care for sick patients, it puts them and our communities at risk!

The WHO and CDC were telling people that masks don't work because there is no good quality evidence to show that masks work, and there's plenty of evidence to show that masks do not work.

Look at the most recent CDC mask advice. They're not saying "masks work", they're using much more cautious language: "masks may work". https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-si...

> there is no good quality evidence to show that masks work, and there's plenty of evidence to show that masks do not work.

Bullshit. Most of all because it's not a binary issue at all. Even if masks reduce the number of particles you exhale and inhale only by 30%, that makes a huge difference for the population as a whole.

> Bullshit. Most of all because it's not a binary issue at all.

Parent comment doesn't claim it is binary, or rest on it being binary. Post good quality evidence to show that marks work.

The guy from Slate Star Codex made a great point about this: Initially, the CDC refused to recommend wearing masks to inhibit virus transmission because there weren't rigorous studies supporting that usage. At the time they must have viewed it as irresponsible to recommend protective measures that weren't properly evidenced.

But, the reason there weren't rigorous studies supporting mask usage was not because they don't work, but because nobody was willing to run a study where you exposed half the subjects to a virus without any protection just to prove that masks would help the other half. It's the same reason there aren't any double-blind studies proving that parachutes help you if you fall out of a plane.

Archive link to the referenced post: https://web.archive.org/web/20200415084132/https://slatestar...

That’s not the primary reason. They selfishly wanted to protect mask supplies for medical use and so spread FUD around public mask usage. It was criminal and people should be held accountable. Masks work for some value and whatever that value is, it accumulates as more people wear masks, and the idiots in charge gave up months of that reduction so that people wouldn’t buy up all the masks at Home Depot. Only they still bought all the masks, and then used the CDC’s own FUD as their own to not wear them and convince everyone else not to wear them.

When I bought my N95 masks in mid february, every Home Depot has already been cleared out and the masks sent to China where they were valuable. I had to visit 5 stores to buy a few leftover.

That was well before the CDC and surgeon general were telling people masks are bad for you don’t buy them. The masks were long gone by then.

I don't consider that selfish. It's like Triage. Healthy doctors and other medical professionals are of special importance in a pandemic, and preserving supplies of protective equipment for them was especially important.

It’s selfish when the advice isn’t “we need n95s, everyone else please at least pull your shirt over your nose”

White lies are still lies that cause people to lose faith in any advice you might have.

Given how easy it is to create home made mask which is better then none, it is absurd.

> That’s not the primary reason. They selfishly wanted to protect mask supplies for medical use and so spread FUD around public mask usage.

No, this is specifically addressed in the SSC piece. The CDC has been against masks for many years; their advice on masks this year was the same advice they've always given. There is absolutely no reason to believe they put any further thought into it than that.

For what is worth: many health authorities world-wide have used the same strategy (conserve mask for healthcare by not advocating/dissuading their use). Taiwan and Korea being notable outliers.

So it is not that the CDC was malicious / selfish / conspiring. They did what they believed was the best policy response. Even if we know better now that they should have just published instructions on making community masks and advocating their use.

> Initially, the CDC refused to recommend wearing masks to inhibit virus transmission because there weren't rigorous studies supporting that usage.

> nobody was willing to run a study where you exposed half the subjects to a virus without any protection

Running the studies is effectively impossible due to ethics constraints. The CDC were probably lying about their reasoning because if you put all these facts together the CDC would not ever be able to take a position on countermeasures until it was clearly too late. I dunno what their idea of Disease Control is for pandemic, but a little bit of "balance of probability" thinking probably happened.

Even if we'd discovered masks were a complete waste of time, the cost-benefit of everybody spending $10 for hastily sewn cloth mask was clearly in favour of recommending the idea. We've had entire economies parked up, I'm sure the labour could have been found to do some knitting. As projects go it would have been a very productive use of time. They just didn't want to disrupt the supply of medical masks and showed a rather dire level of panic and unpreparedness.

Political agenda, or something even more sinister, like an opportunistic foreign adversary? It seems like a lot of the FUD around Covid-19 is deliberately being spread to maximize casualties.

The article points out that contrarians, often conservative, promoted mask wearing until the US government reversed its position and said that masks do work.

Suddenly, anti-lockdown protests, conspiracy theories and mask objecting started happening, and mask wearing became politically polarizing. It would be interesting to see where these people get their information from...one suspects that the answer will be skewed heavily toward social media.

"Political agenda, or something even more sinister..."

I think the simplest explanation is that the conservative right now views literally every issue as a them-versus-us issue, and as soon as it was clear that "they" thought we should wear masks, a very predictable conservative backlash occurred. I'm not sure if the president helped launch this particular battle in the "culture war" or was just a cheerleader as usual.

I'm not sure if the president helped launch this particular battle in the "culture war" or was just a cheerleader as usual

The US government reversed itself on masks and recommended them before the rest of the English-speaking world. The WHO only endorsed masks a few weeks ago. I don't like Trump, but these are facts.

It seems to have been politicized after Mike Pence visited the Mayo Clinic, and didn't wear a mask, and then Trump was then pushed on the issue, and reacted characteristically. If Pence had set a good example and worn a mask, or of there hadn't been a huge uproar about him not wearing a mask, would the issue have turned into a front in the culture war?

> The WHO only endorsed masks a few weeks ago. I don't like Trump, but these are facts.

That's not facts, that's spin. From your phrasing, it sounds like you're saying that prior to a "few weeks ago" that the WHO policy was somehow anti-mask. It wasn't, even in January. Their policy was always that PPE should be reserved for health care workers due to scarcity, and in a few (A FEW) instances their wording of that recommendation was poor and might plausibly imply that masks don't work.

No expert ever interpreted the WHO policy the way you people insist on doing. And at this point this insistence is just pathological.

and in a few (A FEW) instances their wording of that recommendation was poor and might plausibly imply that masks don't work.

Until Zeynep Tufekci's New York Times oped, the consensus was indeed that "masks don't work" for Covid. I documented numerous instances on social media of healthcare professionals insulting and belittling those who wore masks based on what you describe as "poor wording".

Here is a Time article from 4 March that sums up the expert consensus on masks at that point (in fact it has direct quotes from experts, including an infectious diseases professor, a leading psychologist, and the Surgeon General): that masking was "superstitious", didn't work and claiming that wearing a a mask equated to knocking on wood, or not walking under a ladder. https://time.com/5794729/coronavirus-face-masks/

Trump has consistently made a point to not wear a mask, even when the places he was visiting specifically asked him to. Trump has also mentioned several times that he thinks masks should be optional. He has unequivocally and undeniable undermined harmed efforts to promote make mask wearing, and continues to do so.

The US President absolutely launched this when he decided to make the existence - let's be clear, not the severity or the appropriate level of response, but initially it was the existence of a deadly virus - a political issue, and declared it was a hoax while standing in front of the White House.

Can you cite the exact quote where he said that?

https://www.cnbc.com/2020/02/28/trump-says-the-coronavirus-i...

Do your own Googling next time.

That story doesn't even back up your claim.

My question was rhetorical. I know it's not true. I hoped you would look it up and realize your comment was inaccurate.

Foreign information warfare units absolutely want to be stoking that fire to the fullest extent possible.

Their election interference was so wildly successful that they'd have no reason not be trying to inflict further damage on the US now.

What is the political agenda behind it? care to elaborate?

I have interacted with some people who insist being "forced" to wear a mask impinges their rights. My response is, you're right it does impinge your rights. Just like your right to drink a lot of alcohol and drive your vehicle has been impinged because it was decided that my right to live is greater than your right to drink and drive.

I'm a huge proponent of individual rights, but what often gets overlooked in these conversations is that my right to do something often conflicts with someone else's right to do something else.

I just post this: https://en.wikipedia.org/wiki/Jacobson_v._Massachusetts

The people I’ve seen who have a problem with masks are just mad that they are being told to do it. They even acknowledge that there is a good reason but won’t do it because authority figures are telling them to wear them. Total eight-year-old mentality in an adult.

No, I hate mask wearing because it's illogical and being presented as "fact based", "caring for others" etc when this has no basis in reality.

COVID-19 has turned out to be no more deadly than any other seasonal respiratory disease. Lockdowns were ineffective. The data on this is clear and gets clearer every day (though you won't find it reading the stories on HN of course).

That means we should not be doing things any differently to other years. Which includes masks.

> The data on this is clear and gets clearer every day (though you won't find it reading the stories on HN of course).

It's amazing how almost universally visceral, impulsive responses such as this fail to provide references to such data.

Jeez, give me a break. I'm not "visceral" or "impulsive", that's just insulting. Scroll through my comment history. I've been posting links to facts on this for months. And they're publicly available and widely covered in some forums.

Try these sites for a flavour:

http://inproportion2.talkigy.com/

https://swprs.org/a-swiss-doctor-on-covid-19/

https://hectordrummond.com/2020/06/29/this-is-what-we-shot-o...

These links have a UK/Europe focus but the story is the same everywhere.

Re: lockdown does nothing. Take a look at the analyses by the major investment banks. They're all reaching the same conclusions because the data is public and anyone can analyse them. No correlation between lockdown severity and course of disease.

Thanks for providing some references, if nothing else it shows a little effort to validate your points. And I wasn't claiming you yourself are visceral or impulsive, simply your referenceless/dataless claim-making comment appeared that way. Apologies for the misunderstanding, I just get frustrated at the ever-increasing amount of (usually) politically motivated counterpoints made on anything today without the slightest piece of data to support such claims.

The people i have talked with that are concerned with the loss of personal liberties are well aware we have to give up many liberties to live is a society. The part everyone ignores is that most of these people want the legal process followed and to not have rules made by non-checked executive order. They want to know that new rules are based on law and granted powers to rule makers. Just because this particular rule might make sense to you now (“i agree we should wear masks”) does not mean you will agree with the some future rule later. And for that, we have a process that makes new laws and gives powers to make executive decisions.

> It just hardly seems like much of an inconvenience.

Not arguing that any of this is a good enough reason to not wear a mask right now, but, I find them pretty darn inconvenient.

It's very uncomfortable. It fogs up my glasses when I’m inside, and covers up a large part of my field of view even when I’m outside. I can't ride my scooter at all because with that field of view loss, I'm worried I'll crash into something. Talking is more difficult, both projecting enough to be heard through the mask and straining to hear others.

I've tried several different masks at this point, so I don't think that's it.

When I'm doing construction, I often wear a form-fitting N95 mask (for dust protection) and safety glasses.

The top of the mask, and the nose-bridge of the safety glasses, compete for the same location on the bridge of my nose.

If I layer them so that the mask touches my skin, and the eye glasses rest on the mask, I have no problem with fogging.

If I layer them the other way: the eye glasses' bridge directly on my skin, and the top of the mask resting on the eye glasses' bridge, I get fog.

Maybe you're experiencing this?

I usually avoid this simply by putting my eye glasses on after my mask is in place.

It's almost completely dependent on the masks construction. I never had problems with my n95 from 3m, but the kn95 I have is impossible to wear with glasses no matter how I fit it.

The surgical mask a friend got for me in March looks near identical to the pack of masks I got recently besides the color but the one she got me fogs up my glasses while the pack I have now never does.

FWIW, the mask I was referring to in the GP is the GVS SPR457 Elipse P100 [0].

(As a side note, I haven't tried many masks, but I find this one extremely comfortable and effective.)

[0] https://www.amazon.com/gp/product/B013SIIBFQ/ref=ppx_yo_dt_b...

Why do you need to wear your mask while scootering?

I tuck my cloth mask under my sunglasses and this avoids any fogging. Also, don't ride a scooter with a mask on.

Yeah, this part confuses me about GP's description. If any breath is being directed upwards towards your glasses, you're not adjusting the bendable part right to form-fit your nose.

This is why it's mostly meaningless to recommend everyone to wear a mask. Many do not know how to use them properly. And a lot of people can't afford them. If you can even find some to buy that is.

No, this is why the CDC should be running 30 second "how to properly wear a mask" public service announcements.

They've been in stock online, locally at my grocery store, at Target, and at Costco for weeks now. Quite a few stores will hand you a free one if you don't have one (I know Kroger will), and a washable reusable one will set you back a few bucks at most.

If we discovered people weren't wearing their seatbelts enough, getting rid of seatbelts would be a silly mitigation.

Try washing your lenses with a drop of dish soap. That will help with the fogging.

https://www.npr.org/2020/05/08/853009325/how-to-prevent-glas...

So just pull the mask down while you're on your scooter. On the road you're effectively "alone" outdoors.

You haven’t ridden in Manhattan, I suspect. People would get right up to me constantly, even during Covid.

Do you want some nose clips to prevent your glasses from fogging up? Also keeps the mask tight to your face solving your FOV issue.

>I can't ride my scooter at all because with that field of view loss, I'm worried I'll crash into something.

Just how big of a mask are you wearing? No mask I've used or seen would prevent this at all, sounds a bit dramatic to me. Plus, why are you even wearing one while riding your scooter? It's not needed unless you're in close proximity to people.

They're more annoying for some people than others, there's no surprise in that. Still, there are nurses and doctors in disease wards who have been wearing these things full time now for more than three months, so... I think you can deal. Keep experimenting, you'll find something that works.

Or just stay in environments (your home, or outdoors with consistently good distancing) where you don't really need the mask.

Mask effectiveness determines how much of the economy we have to abandon and redesign and how much we can restart before it falls apart. Personally I don't have a lot of hope that modest reductions with loose cloth masks change many outcomes; viral load is extremely nonlinear.

> It just hardly seems like much of an inconvenience.

It's not (for the vast majority of people the vast majority of the time) but the benefit is to other people not you and well acting in other peoples self interest seems to be seen as weakness in parts of the world (including sadly mine).

FWIW I always wear either a mask or a bandana over my mouth/nose when I'm out and about these days not because I expect it to protect me but because it might protect someone else.

I expect my opinion is swayed by my best friend having Cystic Fibrosis for which Covid19 is essentially a death sentence and a mother who has chronic health issues.

From my perspective alongside all the other advice wearing a mask seems sensible.

Same reason I wear heavy duty motorcycle gear and a helmet when I ride my motorbike - I don't plan for the crash but as the saying goes, you don't wear it for the ride, you wear it for the slide.

There's a video on Youtube of some guy blowing vape smoke through various filter types. Pretty much all of them pass it, up to HEPA filter types for vacuums and medical respirators. Some filters I tested will filter particles down to the size of smoke, but Corona-19 is 1/10th of a micron across, which is smaller. It does get filtered by various materials, but those materials need to use static cling to filter. If they don't, the virus will pass through, given the hole size of the material.

If you are hanging around and talking to someone at a fairly close distance, masks simply won't do anything other than visually signal distance is required to others. And, in the unlikely event someone sneezes or coughs, it probably prevents widespread contamination of the surrounding area.

The Seattle choir episode and some studies out of China in restaurant air handling systems seems to indicate the virus is airborne and can be spread to others within a fairly large area, with time and proper airflow. This will happen with or without a mask in place, in my opinion.

I'm super nervous about sharing indoor space with people I don't know, so I don't. The more time we can buy ourselves, the better the outcome.

Masks do a great deal to reduce transmission of Covid-19. (This isn't true of every disease.) Covid-19 is mostly acquired by inhaling droplets of water+virus exhaled by carriers, so masks work quite well. A large amount of evidence for this is collected at https://masks4all.co/facts/

The idea is to stop the respiratory droplets that contain viruses. Droplets measure on the order of micrometers, which is the range that surgical masks are made to be effective.

A Google search result for droplet sizes: https://www.pnas.org/content/115/10/E2386

A Google search result for effectiveness of various masks related to particle size: https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/

Visualizing Speech-Generated Oral Fluid Droplets with Laser Light Scattering[0]

[0] https://www.nejm.org/doi/full/10.1056/NEJMc2007800

If the virus spread airborne rather than by droplets then you would see the effective R value much greater than what the coronavirus is.

Example: measles is spread airborne and the R value is > 10. Coronavirus R value is < 3

I don't know why you are downvoted. There is growing evidence that the virus mostly spreads as aerosol and that the amount of particles you inhale dictates how sick you get. The so called super spread events account for over 80% of the transmission.

Bad ventilation and dry air keeps the airosols floating around making it easier for people to inhale them. The spread in meat factories is one example.

But a mask still can prevent a lot of airosols. While also being limited. There was research that shows a lot of air escapes above and below the mask if someone coughs or sneezes.

"Corona-19 is 1/10th of a micron across, which is smaller."

People seem to have a huge misunderstanding about how viruses travel through air (which is how you get stupid memes like this[1]). There aren't isolated viruses floating around passing through spaces 1/10th of a micron or larger. They need a medium of which to travel upon (such as saliva droplets) that are much larger than the virus itself[2] (usually 5-10 microns)

1. https://starecat.com/content/wp-content/uploads/im-wearing-t...

2. https://www.npr.org/sections/goatsandsoda/2020/04/03/8256393...

I would note that bandanas aren't necessarily the best material for DIY masks. Still better then nothing, but folks may want to take a look at https://www.huffpost.com/entry/best-materials-diy-face-masks...

It is always a balance with risk management. People should wear heavy duty motorcycle gear and a helmet when riding motorbikes, but with cars the same gear is seen as a bit excessive as there are a 30x difference in risk for the two mode of transportation (per distance traveled) and the small but possible risk of a false sense of security might result in worse driver behavior.

If you are near someone in a risk group it seems very good advice to use or even mandate the usage of masks. Same for being around high risk areas such as using any mass transportation. For low risk areas the benefits are less clear and the potential downsides seems to have about as much evidence as the benefits.

Agreed. People could wear similar gear (motorcycle helmet, motorcycle jacket, motorcycle gloves) when driving a car. It'd be inarguably safer for certain types of crashes. I, for one, have road rash on my arm from a car wreck.

But we don't. Because it'd be inconvenient. Safety is not anyone's highest goal.

> What confuses me is why so much scrutiny is being placed on the practice of wearing a mask. It just hardly seems like much of an inconvenience.

In my experience it is a big inconvenience. The air is not properly mixed, so one breathes back part of breathed-out air. With (cloth) facemask, i have shortness of breath after running up a staircase, and after 15 min of regular walk i start hyperventilating.

While i wear facemasks and consider it a reasonable measure, the government mandate was sometimes excessive. For example, at the start of the pandemic, the government mandated wearing facemasks everywhere outside of home, even in nature far from other people. I stopped to do recreational walks in nature, as it was just too burdensome to do that with facemask. Fortunately, after several weeks, the government noticed that mandating masks in nature far from other people is nonsense and made some exceptions.

Wearing masks do not affect oxygen intake.

If what you say is true, all healthcare workers who are wearing masks 8-12hrs a day would be collapsing - and most of them are double-masking with cloth masks on top of N95 masks.

First, it is not an issue of oxygen intake, more an issue of CO_2 elimination. The fact that non-rigid cloth facemasks at least partially block air exchange is obvious just from how they are inflating during exhalation.

Second, i also wondered how healthcare workers could use that for full shifts. Perhaps my experience is related to my health issues (asthma in the past). Or perhaps improvised cloth facemasks are just much worse in this regard than surgical face masks or N95 respirators. Cloth facemasks could have just bigger air 'buffer'. N59 respirators with valve and coth mask on top could be much better, as they would have partially separated in- and out- airflow.

CO2 elimination is also not an issue:

https://twitter.com/MurseWordsworth/status/12767990206738882...

And those with chronic health issues also see no problem with masks, despite having existing pulmonary conditions:

https://twitter.com/G17Esiason/status/1277249837059264512

Basically, the volume of air that your lungs can move, in addition to the force of exhaling/inhaling, easily overcomes any air "trapped" in the mask.

Blood oxygen saturation is not informative in this context, and it's disconcerting to see medical professionals treat it like it is. You can hyperventilate until you pass out without your blood oxygen saturation changing.

> Blood oxygen saturation is not informative in this context, and it's disconcerting to see medical professionals treat it like it is.

Watch the full video. CO2 is addressed.

> You can hyperventilate until you pass out without your blood oxygen saturation changing.

Passing out when you hyperventilate is from too little CO2 rather than “retention.“ The opposite of what is being claimed masks cause.

I did watch the first video in full; the other link, and three others in another post only address blood oxygen. I made no claims about CO2.

I don't think wearing a mask will meaningfully affect the breathing of most people, but blood oxygen isn't meaningful in demonstrating as much.

Passing out from hyperventilation is a second order effect of hypocapnia; the proximate cause is cerebral hypoxia, despite the blood being saturated.

It’s easy to find examples of health care workers complaining about masks interfering with their breathing[1]. That was just the first example I looked at there are plenty more.

[1] https://forums.studentdoctor.net/threads/trouble-breathing-i...

"I feel from the moment that I put them on that I can't get quite enough to breath." That's what they are feeling - they may be claustrophobic, etc. And I believe they are feeling that.

But let's look at actual data - there's no measurable impact on blood oxygen saturation when wearing masks:

https://twitter.com/MurseWordsworth/status/12767990206738882...

https://twitter.com/AlisonKabaroff/status/127738060548793958...

https://twitter.com/DrRobDavidson/status/1277565585568784385

Arguing with blood oxygen saturation is prety much strawman. Nobody here claims that facemasks impact that. Effects of insufficient CO_2 elimination are much earlier. If you were in badly ventilated room with 2000 ppm CO_2, you would feel dizziness even that you would still have full oxygen saturation.

That’s not data, that’s a few anecdotes.

You seemed fine with anecdotes upthread.

https://news.ycombinator.com/item?id=23728608

That’s because even one example suffices to prove an existential claim such as masks can interfere with breathing. That’s not true for universal claims such as masks don’t interfere with breathing.

The claim was "Wearing masks do not affect oxygen intake", not "they can't impact breathing in any fashion".

You'd have to rule out confounding variables like panic attacks, nervousness, etc. - especially in first-time medical workers - and obtain actual evidence of impact on oxygen saturation for those anecdotes to be useful.

You must be confusing me with another commenter. I specifically said: “complaining about masks interfering with their breathing.”

I'd just like to clarify that blood oxygen levels is not what makes you feel like you can't breathe. It's the amount of CO2 in the blood that's the issue. The first tweet addresses this point though.

I'm not entirely convinced by the test shown though. Doing a similar test while doing light exercise would be more convincing.

Another important factor to consider is that people breathe differently. Some people breathe more through their nose, others through their mouth. Maybe this can have an effect? Then there's also the fact that some people can take much stronger breaths (pulmonologists are always disappointed by my spirometry test results).

Mask wearing is important, but it doesn't feel right to just dismiss the reports that some people have more difficulty breathing with masks just because it doesn't happen to me.

My mother who has severe issues maintaining her oxygen levels and has to be on oxygen while she sleeps wears a mask while she's out and about fine.

I'm guessing the issues people face is less about the masks and more about the sensation of wearing a mask which spikes anxiety levels and causes the sensation of being unable to breath. If Japan can reach near ubiquitous levels of mask wearing without issues especially given their larger elderly population, I'm sure they'll be fine.

Otherwise if they have an actual medical issue that prevents wearing a mask then by all means.

> My mother who has severe issues maintaining her oxygen levels and has to be on oxygen while she sleeps wears a mask while she's out and about fine.

"It works for me" or whichever other anecdote is given to dismiss a valid complaint has never held any water and never will.

> If Japan can reach near ubiquitous levels of mask wearing without issues especially given their larger elderly population, I'm sure they'll be fine.

Masks aren't fun to wear, I was out in one yesterday in Japan and my wife, who is Japanese and has worn a mask long before this pandemic was a glint in a bat's eye, was complaining about being out of breath and uncomfortable.

They're well known for being uncomfortable even in the winter, and they have plenty of negatives beyond that.

Besides, if you saw the way people wore masks in Japan you'd never use it in an argument.

"... even in nature far from other people"

Yes, some governments issued nonsense warnings like this. But don't let the dumb proclamations of a few politicians impact your overall opinion on mask usage. These days, most guidances seem to be largely fact-based, thank god.

> With (cloth) facemask, i have shortness of breath after running up a staircase, and after 15 min of regular walk i start hyperventilating.

Talk to a doctor. This is not normal. Running up a staircase is done with oxygen in your tissue, it doesn't involve breathing per se, your body buffers all that you need.

And regardless: there's not NEARLY enough air space behind your mask to store a full (~1L) exhalation. What you claim isn't even physically possible. Gas goes through and around the mask and mixes with your environment.

Frankly, (and I don't say this in spite, I promise!) your symptoms track more closely to anxiety than to any physical problem. Talk to your doctor, you'll probably feel better about things.

People with actual breathing difficulties do, in fact, experience symptoms like that with masks, which do aggravate them (I believe by increasing the proportion of rebreathed air, slightly lowering O2 concentration which can be problematic combined with existing breathing problems.)

It's also possible to experience symptoms like that (thought usually also with intense itching and other sensations that make it clear that it's an allergy) if the max contains an allergen to which you are sensitive. (Some masks contain latex, which is a not-super-uncommon allergen.)

> And regardless: there's not NEARLY enough air space behind your mask to store a full (~1L) exhalation. What you claim isn't even physically possible.

According to Wikipedia, normal level exhalation (tidal) volume is ~500 ml and has ~5 % CO_2. If only 10 % of exhalation (50 ml) is breathed back with 90 % of fresh air, then one is breathing equivalent of ~5000 ppm CO_2.

I am sure that improvized cloth facemasks have bigger air 'buffer' than this. Although measure it precisely would be hard.

I have a hard time believing your air mixing argument is a big issue for most people. Tonnes of people go snorkelling and don't experience the type of problems you mentioned. When you inhale the air inside a snorkel is more likely to have just been exhaled since it doesn't have anywhere it can go. To me this suggests your issue is either psychological or you have something else compromising your respiratory system and should definitely be taking every precaution against covid that you can

Apparently this was an unpopular opinion so I went back and checked the math. A snorkel is about 18 inches long with a diameter of 0.75 inches. This gives it a volume of 7.95 cubic inches or 130 ml. The poster I replied to suggested, in another comment, that rebreathing volumes as low as 50ml could be problematic. If that were the case you would run into major issues with snorkeling.

I am not saying that there aren't people that have difficulty breathing in masks. I am saying that having difficulty wearing a mask is not normal and you should discuss it with your doctor to find out why.

Because laws are being made based on weak science.

Like lead paint or Thalidomide masks may only seem to be positive on the surface.

Without proper science it's wrong to make laws about it.

> So then why so much effort into deciding if it works or not?

A lot of members of society view not wearing one as an act of courage. A friend's mother will tell anyone she encounters who is wearing one that they are a ninny and a coward. So for some people it is also an indicator of courage/weakness.

A study lets me tell her she is an idiot. Preventing others from being called also cuts into the "ninny" narrative.

In addition, the science has changed over time.

It seems like skin contact isn't quite so likely to spread the virus but breathing in exhaled droplets is.

Incidental interaction doesn't seem to spread the virus that well, so wearing a mask significantly reduces the risk to people like your grocery clerk.

It seems like general contagiousness isn't the primary mode of transmission, but instead the vast majority of cases come from superspreaders.

All of those indicate that mask wearing is probably more beneficial than expected.

If skin contact were the primary mode, then masks would likely have downsides as they tend to provide a warm, wet spot for the virus to hang out until you touch it.

Surely she’ll sit down to read that NEJM paper and be appropriately chastened.

No, but she generally isn't willing to call the doctor who did the study an idiot or fraud.

> And common sense dictates

Evidence based medicine doesn't exist to protect us against crystal healing (the bullshit that we know cannot work). It exists to protect us against things that sound plausible, against things that sound convincing.

The problem with the "wear a mask" message is how lazily anti-science it is, and how it distracts from the more important message of "keep your distance" and "wash your hands".

People who promote mask wearing say three things:

1) Masks work

2) They work well

3) We have good evidence for this

In healthcare good evidence would be a well run meta analysis of well run RCTs, or well run RCTs. We have lots of randomised controlled trials for mask wearing to prevent spread of respiratory disease. If masks were so strongly effective it would be easy to see the benefit in these RCTs. So why don't we see these benefits in the RCTs?

We have lots of good quality evidence around masks, and it doesn't show a benefit. For use to be able to see a benefit we have to drop the quality of the evidence, and then we start to see some marginal benefits of FFP3 type masks, but not for fluid-resistant surgical masks, and certainly not for cloth face coverings.

The message could have been "we don't know if they work, we don't have the evidence yet, but you should wear one anyway".

Instead we've got this bloke...

> “Back in March, it was difficult to even have anybody take you seriously when the CDC and WHO said the opposite,” said Jeremy Howard, a data scientist and entrepreneur who has become a major advocate of universal mask requirements. In response to the lack of support, he launched a bipartisan campaign called Masks4All that lobbied for widespread mask-wearing and argued that masks were a crucial, if not the most important, part of the COVID-19 response.

...ignoring the science around handwashing and distancing and focusing on mask wearing.

> “The problem with the "wear a mask" message is...it distracts from the more important message of "keep your distance" and "wash your hands"

I don’t get this impression at all. In fact, I was thinking that if someone wears a mask, then they are more likely to be doing the other things (more or less reliably)

I agree, I was in Tokyo at the beginning of this and every one just put a mask on, the subway, everyone wearing a mask, no questions asked.

I believe people there know that it's for the benefit of others but they understands that if everyone does it, everyone benefits? Unusually, this can be hard for people to understand.

Yes, this! Japan's population is 38% of the US population. And yet they have seen about only 1000 coronavirus deaths to date. I have to believe this is because they just do what they're told without defiantly rejecting the advice of health officials or otherwise doing a bunch of armchair sciencing that leads nowhere.

Why trust the figures coming out of Japan? Were the lies around Fukushima not enough to bring a hint of scepticism? Or maybe this blog article[1] which was on the front page of HN[2] a while back?

Japan has a culture of conformism enforced by social pressure, and many places are now mandating that they be worn, that's why the masks are worn en masse of late, but often they're worn for privacy when you've little personal space. People still don't do what they're told and there's basically zero social distancing even where there's markings to guide people.

[1] https://stdio.sangwhan.com/wtf-japan-covid-19-report/

[2] https://news.ycombinator.com/item?id=22728674

Just notice that this particular article managed to say nothing in so many words.

I think it's mostly a variation of your second option. It's not so much that the people in question are concerned with the minor inconvenience (as discussed in the article, and many of us saw early in the pandemic choosing of sides, they were in favor of masks when it was contrary to the recommendations from experts), and it's not so much that they've been led to believe something unwittingly. The reason it's such a controversy, is because opposing the other side has become reflexive.

Exactly - it’s become an in-group signal due to Donald Trump politicizing mask wearing.

> ... have been led to believe that mask mandates seriously impinge upon their rights.

This is vastly amusing. Before late 2019, folks like me complained about laws against wearing masks in public. At protests, for example. While mailing stuff, or buying money orders. To circumvent facial recognition.

So now when I go out, and everyone is masked, it feels like such a bloody victory! Except that it is uncomfortable, when it's hot and humid. But hey.

> It just hardly seems like much of an inconvenience.

For me, some who has been wearing masks since before it became government mandated (though I recently stopped outdoors unless it’s crowded, as we barely have any cases; and it’s not as if more than 1 in 100 wear one outdoors anyway), masks are the single biggest inconvenience of the whole Sars-CoV-2 pandemic. I become slightly more claustrophobic (when in a store) and it feels like I have slight trouble breathing properly.

As I said, I’m a mask proponent, but I feel like all those statements of "wear a mask, it’s nothing" are hurting credibility.

All of that being true, I would like to add that in pursuit of being rational and scientific, I would really like to know to what fraction of spread of virus is affected by any measure that we take (here: wearing masks, when we wear them or where we wear them). For me it's a matter of satisfying my scientific curiousity. Of course one shouldn't stop taking those measures seriously in that pursuit.

Masks don't halt aerosol transmission of the virus. Every breath you exhale is an aerosol. What you feel passing through the gaps in you mask when you exhale is aerosol and, if you have Covid-19, it is Covid-19 infected aerosol.

Nothing except an airtight seaal can stop it.

From an outsider perspective (I'm Canadian), the politicalization of wearing a mask seems like a huge distraction from action that can make a much bigger difference:

* staying home when even a little bit sick

* physical distancing (esp. indoors)

* hand washing

* don't touch your eyes, nose, mouth with unclean hands

* getting tested if having symptoms

* if physical distancing is not possible, then wearing a mask (esp. indoors)

I kind of worry that in a desperate attempt to improve the economy, US governments will continue to ignore the advice of experts and embrace mask-wearing as a panacea.

US governments have to deal with the fundamental problem that the US public doesn't want to physically distance anymore. They want to gather with friends and family, eat in restaurants, drink in bars, even hold large public gatherings for their political causes. If the government doesn't offer advice on how to do these things safely, that'll just mean they get done unsafely.

Was it ever the plan to maintain physical distancing for the next several years? As lockdowns started, the most alarming projections had us cycling it on and off periodically. Not going cold turkey on all human interaction for the long haul.

Those projections called for a long initial period, long enough to drive transmission to near-zero, which hasn’t yet happened in the US.

> As lockdowns started, the most alarming projections had us cycling it on and off periodically. Not going cold turkey on all human interaction for the long haul.

The projected initial period of lockdown before going into cycling was longer than even the places that locked down early and reopened late had it, and that was assuming coordinated national response not many places not initially participating in the lockdown.

This article has some interesting points, but overall it is click-bait.

The recommendation at the end is, “We don’t know how well cloth masks work, so distancing should come first, but masks are likely to work to some extent and not everyone can distance themselves.” But for most of the article it talks as if the whole matter is so uncertain no recommendation can be made.

Anyway, the whole idea that we should wait until the science is all settled before we make policy decisions is quite impractical. We are learning as we are fighting the epidemic, and so we have to make decisions before we have full evidence. Indeed, the only way we can learn if masks work to help stop the epidemic is to have some countries mandate them and compare the results with countries that don't. Epidemics are very different than individual diseases. You have to make decisions at the group level, and when it is a new disease you have to do so without really good understanding.

And we know that the countries that have pursued a whole set of rigorous policies that includes face masks have been successful, while countries that are lax, include face masks, have failed. So the smart thing to do is pursue the set of policies that includes face masks, and later on find analyse the data and find out exactly how important they are.

I would like to see more discussion around, if the initial viral load is related to the severity of the infection[1].

If yes, then in theory, a mask could provide large benefits, even in absence of a perfect seal around the face.

[1] https://www.lesswrong.com/posts/3ArEA7tHDXQxE6PED/taking-ini...

Absolutely.

The initial disinformation campaign by the western governments (and the CDC and the WHO) that masks are useless for their wearer (due to the shortage of masks, and the fear they won't be enough for the health care personnel) has long lasting effects.

That was an abject lie, and people have paid with their life for that.

The governments now don't know exactly how to turn around and communicate that yes, masks are useful, we've been lying to you all this time, sorry for that, now you can go ahead and wear some.

You can't do an 180 like that, can you? So for now it's "masks are good for the others, but they won't help you. but don't you want to be a good team player?".

What is stopping individuals from holding a nuanced understanding of politics similar to this comment?

Indoctrination to their social circle (family, friends, etc). You'll become an outsider by expressing opposing opinions.

This is a good read “The Masks Masquerade” by Nassim Taleb of Black Swan fame:

“First error: missing the compounding effect” ... “Third Error: Mistaking Absence of Evidence for Evidence of Absence” ...

https://medium.com/incerto/the-masks-masquerade-7de897b517b7

I liked his point that if you believe in "cause no harm" (non-agression), you should wear the mask. It raises issues in what counts as real harm/aggression (wearing clothes someone in society dislikes is technically "harm", but not a harm considered real or aggressive or... I forget the terms).

Then he insults everyone who disagrees with him multiple names and accusations of bad faith (which makes serious discussion undesirable and difficult). I think that's a thing Taleb does (online).

Here in NZ, masks were never required. The rationale is that when people wear masks no matter how you explain it they believe they themselves are safe, which makes them get closer to other people (I can't give them the disease) and be less cautious in general (I'm protected). Take the mask away and the only things they have is social distancing and being obsessive about touching surfaces. Which in my experience works very well and it's what the community here focused on.

In the meantime my folks in Maine wear masks and gloves and think now everything is fine we can do anything and go anywhere.

As timer notes in another post below, the episode "Special Episode: Masks and Science"

talks about the history of masks vis-a-vis Covid-19:

https://www.cidrap.umn.edu/covid-19/podcasts-webinars/specia...

In this episode, Dr. Osterholm and host Chris Dall discuss the current science on COVID-19 and cloth masks.

Transcript available at

https://www.cidrap.umn.edu/revised-mask-transcript-6220

I wear a mask. I encourage all my friends to wear a mask. It's a very low cost, with large potential upside. There's no good reason not to wear a mask.

But I am also interested in the pure science & am asking strictly from that point of view. Again, I am not suggesting we don't need to wear masks.

I found this report on the CDC website that states:

"Although mechanistic studies support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza"

(emphasis mine)

https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article

I'm aware it's for influenza & not COVID-19, but most research, including evidence suggesting we should wear masks, is based on research done on influenza. I think it's reasonable, given the paucity of COVID-19 data and we have to do something, and given they're both RNA viruses, experts feel it's reasonable as well.

My conclusion from above is that while we should still definitely wears masks, it's unlikely wearing them will see a noticeable change in R0, which is what we need to really open up. I.e., opening with mask compliance probably isn't going to work, and we need people to stay home.

I'm not an expert, so would to love to learn if I've got anything wrong. Thanks in advance.

The virus is in the same class as some common colds. It's not "going away". If people are concerned about it they should use a real mask designed to filter viruses[1]. Instead, the population is being conditioned to force medical procedures on other people. Forever.

The "flatten the curve" thing was predictably re-goalposted.

There are strong financial incentives to keep people irrationally in a state of fear. After this, there will be the next.

This keeps getting ignored: What is the non-COVID-19 pneumonia # for 2019-2020?

CDC Influenza and pneumonia deaths by influenza season and age: United States, 2008–2015: https://www.cdc.gov/nchs/data/health_policy/influenza-and-pn... (these are not estimates, see the footnote)

  CDC #'s 2015-2016
  Flu: 7,961
  Pneumonia: 131,858 
  All: 1,769,940

[1] https://news.ycombinator.com/item?id=22232633

> If people are concerned about it

Until more is learned about covid-19 people should be concerned. Where the disease is out of control, hospitals are filling up and many people in need of health care are suffering as a result.

BTW, at least in Canada, the number of deaths due to covid-19 has been concentrated most in long-term care homes. These are also places where deaths due to pneumonia and flu are common. We're learning now that the quality of care in these homes has been insufficient to deal with covid-19. All of the measures that are now in the works to improve the quality of care in those homes should have the side-effect of reducing deaths from other infectious diseases in the future.

The excess death stats are accessible to us all. What's the non-COVID-19 pneumonia # for 2019-2020 so far?

It's nonsensical to expect everyone to agree, those that want a mask, should use one for viruses. This is like pretending the cold is going away, and we must all obey until that happens. Wont happen.

As you mention, fixing the situation of the vulnerable is the way. Quite possibly would have been better response in the first place.

Viruses are only getting easier to engineer. Shutting down the country only makes them _more_ valuable.

Also, deliberate problem: https://news.ycombinator.com/item?id=23741888

"Martin worried that wearing masks might lead people to feel more safe than they actually were — and make choices that increased their risk of contracting or transmitting COVID-19." - I don't see people wearing masks jumping into my face. It's people who're feeling safe for other reasons, that do. People who don't see there's a pandemic. People who think it's all made up. People who feel invincible or who're thinking they can show-off as invincible to impress others. Those people don't wear masks and throw one Corona Party after another. I'd assume that most people wearing a mask care more deeply about others than those who don't. So, wearing a mask is also a statement. And it's got almost nothing to do with politics.

> “... a public health and disease expert who is worried that mask effectiveness is being over-hyped...”

Medical professionals have their own sources of information (just talk to a doctor about hand washing vs. hand sanitizer).

Then I assume the concern is some members of the public are taking risks while wearing masks, thinking they are more safe than they really are? I don’t understand the concern, because if you’re really concerned about the virus you’re staying home. If you’re cavalier about the whole thing, then you’re likely standing <6feet and doing other “risky things”. And finally, for everyone else there are the simple rules.

This seems totally different than, say, the controversy about the anti-malarial drug, which had severe potential side effects.

What am I missing?

So what is needed to get to that certainty? What research is being done or must be done?

Should we even bother, now that masks are becoming easier to purchase?

Given that we're heavily inconvenienced by the masks and other measures, we should find out how well they work so we can focus on the stuff that helps the most.

Crowded Brooklyn bridge and other areas during during Floyd protests: lots of mask usage, no uptick in cases. It could just be that outdoors in sunlight is relatively safe though and that had a bigger effect than the masks. Or just even though it looked like huge packed crowds it was still tiny relative to NYC population.

The CDC best estimate is that US has 20M+ covid cases right now ( https://www.nbcbayarea.com/news/coronavirus/cdc-says-covid-1...) . That number has beem reached with all the masks wearing and lockdowns.

So, what is the difference between the expectations in case of mask wearing vs. not wearing by the end of the year? Even with masks wearing and lockdowns we're probably talking about high tens of millions or even 100M for US. Can it be higher without masks and lockdowns? Spanish flu infected just under one third of total population. For covid, New York had probably reached about 2M cases (~20% of population) and the infection rate went down after that. Using that model of 20% (and NY has much higher population density) it means 70M infections for the whole US. Given how we've already reached 20M+, i think that number will be reached no matter what in a few months (give or take a bit depending on masks, lockdowns, etc.), well before wide availability of vaccine.

So, it is really not about whether masks work, it is about whether it makes any noticeable difference in the current situation. I personally was for total population mask wearing, temp checking, etc. back then in Dec/Jan/Feb because back then we had a chance to stop the spread. These days i just don't see any arithmetically consistent way to avoid the described above scenario and stop the current flooding/tsunami.

The places surging right now in the US are all places where mask wearing was a controversy and many people did not wear masks. So I don't think it is fair to say that the case numbers are "with mask policy".

You assume here that NYC's numbers went down via some property of the disease, not a lockdown being observed by the whole city along with high mask usage. Letting this "run its course" would spike NYC and the whole US far above 70M cases. We would easily be looking at 500,000 dead at least even with how we've learned to decrease the death rate. That death rate would also go up as we stop flattening the curve, as we saw happen quickly with Texas.

NYC has had decreasing numbers despite large outdoor protests, which had high mask usage. In a week or two there will be some numbers on how Phase II reopening is going in an area with high mask usage as well which should be another good data point.

Here are some actual interesting scenario tools for controlling the virus even as it runs its course: https://ncase.me/covid-19/

As a note, a big factor here is that it appears that antibodies may only last for 2-3 months which breaks some of those recovery models. If that is true, without any mitigation and even with most at-risk people dying off earlier, we could still end up losing .1% - 1% of the population every 3 months until we have a treatment or vaccine. I don't like how those numbers look even if we manage to get a vaccine in 12 months.

>some property of the disease

it seems that only some share of people is susceptible to a given virus like covid, flu, etc. (for whatever reason, like some genetic characteristic or for example presence of antibodies from some other virus which happen to help here). Say for example half of the population, 50 out of 100. So once 20 people got it, there are 30 left to be infected while all the others - 70 - can't participate in the infection spread, and 70% is pretty close to herd immunity.

Add to that the estimates that herd immunity for covid can be even less than half https://www.usnews.com/news/health-news/articles/2020-07-02/... - that would explain the infection rate drop in NYC.

> Say for example half of the population, 50 out of 100.

I think you're confusing susceptible and immune. If the antibody numbers are legit, then the asymptomatic rate is around 90%, but that's not the full story. You have to remember that asymptomatic people still spread the virus, so this plays differently in herd immunity modeling. You're still looking at a 1% average death rate in NYC too given those numbers.

That 50% of people you mentioned is not about symptomatic - they must also not be able to transmit. Otherwise using a SIR model or similar there's still 80% of the population that can catch and infect others. I have seen nothing about such natural immunity in people even in small numbers, let alone at 50% of the population. That assumption is doing a lot of legwork in your herd immunity claim.

At best, your assumptions still means we need to accept just under a million deaths. At worst, even with no increased death rate due to hospital load, that's closer to 3 million. When other countries have shown clear alternatives by taking measures that don't lead to 1% of their population dying (such as Germany at 0.01% so far), one of which is mask usage, I don't see how there's harm in the policy when it could mean literally saving millions of lives.

All of that relies on antibodies lasting, which doesn't seem to be guaranteed[1], as I pointed out in my post before. That can make this much worse if/when people begin to catch it again.

[1]https://www.cidrap.umn.edu/news-perspective/2020/06/chinese-...

NYC made masks law on April 15. Germany somewhere around a week later.

> I don't see how there's harm in the policy when it could mean literally saving millions of lives.

there is no harm. I wear my. Even though all the facts and math shows that it doesn't make any noticeable difference at this point.

>At best, your assumptions still means we need to accept just under a million deaths

accept or no accept, covid doesn't care. Anyway, we have already "accepted" it by letting it develop into the current scale. I think original Fauci deaths estimates - up to 250K - made under obvious political pressure to voice lower numbers than he'd do otherwise - is pretty close. From the current 20M+ we'd get 3-4x with death rate falling, thus we'd get into 250K-500K range. I don't see how masks or lockdowns, which haven't been able to stop us from the 10000x jump - tens/hundreds cases into tens of millions - are going to stop us from the 3-4x or even 10x (if the 10x were possible in the current situation which it isn't because the herd immunity threshold looks to be significantly lower)

> NYC made masks law on April 15. Germany somewhere around a week later.

And you left off that NYC's cases dropped the entire time those mask policies were in effect. We didn't isolate for it as the lockdown was in place, but there's at the very least a positive correlation, and the lack of spike from the protests supports that too. I don't see why you jump to defeatism from that evidence.

You're assuming people in most of the US paid attention to the laws and advisories. In Florida for example, mask usage was incredibly low and has caused the spike there. Same for Texas. We don't know if masks would stop the initial jump because we didn't use them. All evidence from other countries points to the conclusion that they do help in a meaningful way.

If you're saying you don't believe the American populace is capable of following instructions, you might be right, but if we actually enforced and practiced mask policies, it very much appears it would make a meaningful difference.

>And you left off that NYC's cases dropped the entire time those mask policies were in effect.

you're right. I somehow was under impression that the peak cases were a month later there. Lets see. I'm still really not optimistic giving the current scale of the spread.

It's been really interesting to watch this pandemic from Japan, where I've been for the last ~3 months. I am an American citizen.

Walking around Tokyo this week I'm still seeing mask rates of >95%. Lockdown ended about 2 weeks ago.

In America, mask-wearing carries a different set of social signals. It seems that not wearing a mask is perceived, by some, as a signal of one's virility and freedom.

The article makes this all pretty clear, but the comments here are getting bogged down in "but the data says masks are/aren't effective". The point is that the data doesn't matter. Mask-wearing is determined by social/political expectations and signaling, not by data.

If a study came out tomorrow that said mask-wearing reduces transmission by 95%, Trump still wouldn't wear one. Looking for a silver bullet study to prove a point either way is a waste of time at this juncture.

Apparently, asking Americans to show that they care about the health of another American via a very low-impact signal (the $10 it costs to get/make a mask, the minor inconvenience of wearing one) is too much.

How can a society solve any size of a problem when it cannot be bothered to put a piece of paper or cloth on their face for the possible benefit of another? If your political climate makes such a minor gesture controversial, how will you solve any meaningful issue where your factions disagree?

How do you get Americans to care about the health and welfare of other Americans?

since "looking for a silver bullet study to prove a point" is the only thing fivethirtyeight has left, it should probably just stop now

> How can a society solve any size of a problem when it cannot be bothered to put a piece of paper or cloth on their face for the possible benefit of another?

A friend's mother will tell anyone she encounters who is wearing one that they are a ninny and a coward. So for some people it is also an indicator of courage/weakness.

> Walking around Tokyo this week I'm still seeing mask rates of >95%. Lockdown ended about 2 weeks ago.

I currently live in Asia and have been for many years, I am from a western country. I think in Asia, face masks are just a fact of life, including pre-covid. There is/was an expectation that if you are sick, then you should probably wear a mask. Given that a lot of cities are crowded, many wear masks also not to get sick.

As a westerner, I understand the negative connotations of wearing a mask, it is not a part of "normal life" in many countries. But life has changed, people should get used to it. Americans should just look at the stats to know that there is a problem. This isn't an attack on their freedoms, it is an attempt not to save their life, but the life of a fellow American, by preventing the spread.

While China may have been the epicenter of the virus, the spread is the responsibility of the citizens of the secondary country.

>How do you get Americans to care about the health and welfare of other Americans?

First, you have to get them to care about their own health. 42% of Americans are obese and heart disease kills ~650,000 Americans every year even though it is largely preventable.

https://www.cdc.gov/obesity/data/adult.html

This seems like it is casting uncertainty when there is really good evidence that wearing masks is effective.

https://www.theguardian.com/commentisfree/2020/apr/04/why-we...

It's effective but it sounds like the fear is that the effectiveness is overhyped (says this specifically in the article)... and I think that's a valid concern.

If everyone thinks they can go out wearing a mask and forget about distancing and other measures, then that complicates things. Wearing a mask to go grocery shopping for 20 minutes is also different than say, wearing a mask and sitting in a theater or bar for 2 hours.

The actual fear should be from people who dont wear masks, dont wash hands and generally act like covid-19 is a hoax.

It does not even matter whether the non-mask wearer is not wearing it because he believes mask is not effective, mask is not needed due to covid not existing or mask is sign of being fearful and one gotta project bravery.

Mask wearer who skipped washing hands once or approached someone 1.5 meters is still good.

"The actual fear should be from people who don't wear masks"

I don't understand this. The actual fear should be any form of scientific misinformation. Eventually, the truth will be known, and if "scientists" are deemed to be advocating for policies that aren't supported by science, it will hurt science in the long run.

On top of this, there is decent reason to believe that there's a down-side to mask laws: too many people think that they can behave normally if they're wearing a mask, when the evidence simply doesn't support it.

>On top of this, there is decent reason to believe that there's a down-side to mask laws: too many people think that they can behave normally if they're wearing a mask, when the evidence simply doesn't support it.

I have seen this repeated many times but have not seen any evidence that really supports it. It just sounds like a common behavior. I would imagine the cross-section of people who are already going to act like it wasn’t a big deal and people who wear a mask that act like it’s not a big deal is already substantial. And while I also don’t have any data, I think it is as common sense as the other assumption and thus illustrates my point.

Also an anecdote, but I know many people IRL who have said "The reason we should be able to open back up is everyone knows to wear a mask now."

That doesn't mean people shouldn't wear masks, but... it's definitely the wrong takeaway.

Anecdotally, people give you a fair bit more space when you’re wearing a mask and clearly taking precautions than if you aren’t. I’d argue that in the current political climate, mask wearing might actually improve distancing measures. The people who aren’t wearing masks just don’t seem to give a shit. It’s a social signal about if you care about covid these days. I’m saddened that we can’t just make tonnes of melt blown and make n95s (that imo are more comfortable than normal masks cause they aren’t touching your lips) for anyone who wants them.

For what it’s worth, thus seems correct in my experience. I expected people to just throw on masks and behave “normally,” but the opposite seems to have happened - it serves as a reminder of the seriousness of the situation.

> On top of this, there is decent reason to believe that there's a down-side to mask laws: too many people think that they can behave normally if they're wearing a mask, when the evidence simply doesn't support it.

But you are just making that one up. You don't have studies showing people wearing masks taking more risk than non-masks wearing people. Also, the scientists talk about effectiveness of masks it is not like I had seen a single one claiming it is perfect.

This whole argument is just being manipulative. Trying to pretend it is all about science and precision, when it is nothing like that.

> too many people think that they can behave normally if they're wearing a mask

I don't know how most people are thinking, but it's a pretty wide spread idea that masks (apart from the ones used in health care settings) are more for protecting others from you, than you from others.

If people are thinking like this then it seems logical seeing someone with a mask would remind them that the asymptomatic can be a threat and encourage distancing.

On the other hand, if most people are wearing masks then the few who don't stand out as abnormal, and so others might be wary of them too.

I guess your generalization might be applicable to some states/cities more than others; under current circumstances, I think most people are not seeing what it's like in other places first hand.

Also, well fitted N95 style masks are very different from a loose mask around the face.

Still makes a world of difference though, especially because your mask (unless N95) isn’t for you as much as it’s for others. If two people interacting are both wearing - even loose fitting - cloth masks over their nose and mouth, the chance of spreading disease is orders of magnitude less.

We do not actually know that. That is the point.

We actually DO know that

Well, then where is the scientific evidence that simple masks reduce chance of spread by an order of magnitude, as described?

There is none, because the science hasn't been done. There's a viral JPEG on the internet that claims this, it's just that.

If we don't have that evidence, the we don't really know, plain and simple.

That's not to say people should stop wearing masks. It's plausible that they help. It's just that we don't know the extent to which they help.

Widespread Use of Face Masks Could Save Tens of Thousands of Lives - https://www.npr.org/2020/07/03/886905055/widespread-use-of-f...

That's a projection based on assumptions on the efficacy of masks. The point is that we don't have a number for that efficacy. We just don't know.

People are talking elsewhere in the thread about glasses fogging up. That, even with an extremely non-airtight mask, that is reused, touched constantly, etc. seems like prima facie evidence to me that it deflects the stream of droplet-laden air from your face, thus inhibiting it from spraying on to others.

Like others have said, if this were a different disease, maybe it would be spread more by contact and masks wouldn't be worth bothering.

And if you're only focused on how a mask can protect you, maybe it doesn't help that much. But if you are infected without knowing it...

Edit: my pun was unintentional...really, I swear.

But we literally do. Do a cursory google search. Hell even Pence wears one.

Masks have always been controversial, but I think what we have seen in terms of outcomes in the NY/NJ/CT area shows that they likely have some effect.

Usually the studies that knock masks compare them against people following good hand washing protocol. Mask vs. person with good hygiene is different than the typical slob you find on the street.

There's no uncertainty that unfit around the nose masks have giant centimeter squared open gaps. For protection of the wearer they're not good. Objectively in tests with similar gaps the rating is N30-N40.

There needs to be a strong and lasting push for increased N95 mask production or at least purchasing. Pretending that ineffective unfit masks (of any material!) can fill the role of real masks does real damage and needs to stop. If everyone could rotate a set of N95 masks when indoors then spread could really be stopped.

Even a synthetic/cotton/synthetic mask would be quite effective if they'd just incorporate metal nose bridge with foam.

Better-fitting masks made of non-woven cloth might help, but the focus on N95 and the confidence that "spread could really be stopped" by wearing them is exactly the kind of overconfidence the article warns against. There's no known evidence supporting the idea that good masks are a silver bullet.

N95 is what doctors wear to generally not get sick while working. Had there been enough of them, it would likely do a lot.

But back to real world, cloth masks is what we got.

I think I've read that N95 masks are in fact inferior to other kinds for "civilians" and I don't altogether believe this is propaganda to conserve them. It makes sense, doesn't it, that N95 masks filter air coming in, not out? My impression is the valve in masks that have them is a sign that it's not protecting others from you - the point is to let air out easily.

There is an asymmetry between healthcare workers and the public - in a hospital, you have one non-infected person surrounded by a lot of infected people, while elsewhere, it's the opposite.

I see a lot of people wearing surgical masks, and having just googled and read a page on 3M's site, it mentions:

"Surgical/procedure or “medical” facemasks are designed to help keep spit and mucous generated by the wearer from reaching a patient or medical equipment. Some surgical/procedure masks do contain filter media but as they may not be designed to form a seal to the face, and have not been certified to meet all of the performance standards of a respirator, they should not be used to help reduce exposures to airborne particles"

I feel like this is a simple difference that people can't comprehend due to a very primitive equation of protecting oneself and protecting others. There is a difference and it should inform our behavior.

Edit: to clarify, I meant to contrast the N95 masks with a valve, that seem to make more sense for health care workers, with the surgical masks that seem to make more sense for the public.

This isn't about protection of the wearer, it's about prevention of spreading.

In that sense what has changed is the best guess at the main mechanisms of spread. Specifically the amount of spread mediated by large spittle on surfaces versus via aerosols. It has become increasingly clear from large spreading events (meatpacking with gloves/hygine in place, singing events being really bad) that aerosol spread is primary.

So the protection that unfitted cloth masks provide, and it is some, isn't as much as you'd think against the primary mechanism of spread. Wear an unfit mask and sing and it's as bad as normal singing.

I'm not arguing for not wearing bad masks when it's all you have. I'm saying it's super important that everyone starts getting real masks so we don't have to keep doing shelter-in-place every time spread goes exponential in an area again.

It's currently believed SARS-CoV-2 spreads primarily via droplet, not aerosol.

Singing propels droplets further (as does any heavy/forceful breathing), and choirs tend to sit close together. Six feet likely isn't enough for a choir.

As for meatpacking, I've heard several interviews with workers that indicated the plants were only handing out one mask per shift, and they'd pretty quickly get contaminated by gore from the work, meaning in practice folks weren't wearing masks.

Right. I just want to further highlight that "aerosol," in the context of medical journals, has a specific meaning, and that your lungs generally aren't capable of aerosolizing the virus into small enough matter to qualify. The spread from coughing, sneezing, etc, is still considered droplet-based spread, NOT aerosol. Droplets can still be suspended in the air for a matter of seconds, however.

MAGZine says>" your lungs generally aren't capable of aerosolizing the virus into small enough matter to qualify."

No, every exhalation is aerosol and filled with particles from your body. They slip by the mask's edge and through it's seams. No mask that isn't airtight can stop those particles.

Droplets are emitted when you cough or sneeze and are much larger. Droplets are like boulders, aerosol like marbles. Viruses are tiny compared with aerosols and ride on both aerosols and droplets.

No, it was at the start. Then after a few months everyone who was reading the journal articles became aware that aerosol was the mechanism of spread and that normal human behaviors created aerosols that worked for this. The WHO and governments have lagged because they don't want people hoarding effective masks when hospitals need them more. But they can't deny reality for much longer and it's time to manufacture more instead of lying about spread mechanism.

"239 Experts With 1 Big Claim: The Coronavirus Is Airborne" https://www.nytimes.com/2020/07/04/health/239-experts-with-1...

>The W.H.O. has resisted mounting evidence that viral particles floating indoors are infectious, some scientists say. The agency maintains the research is still inconclusive.

On the contrary, there's actually very little evidence that masks are effective for the general public. Particularly for cloth masks, the evidence is essentially non-existent. You're citing an article by Jeremy Howard, who is quoted in the OP, and whose opinion is directly rebutted.

Michael Osterholm of CIDRAP has written a rather scathing summary of the data for cloth masks, and the political and social machinations that have gotten us where we are. He calls out Jeremy Howard as a particularly vocal spreader of scientific misinformation on the topic:

https://www.cidrap.umn.edu/covid-19/podcasts-webinars/specia...

(edit: how can you possibly downvote a link to a factual source that is cited in the article? Consider your bias.)

In my opinion, it's unreasonable to expect that there would be studies on the effects of cloth masks. Up until the quarantine began the reasonable assumption was that if you needed a mask you wore the one appropriate to your task. I don't think cloth masks were in widespread use until these masks became scarce.

Maybe some studies are happening now. Even so, it probably makes more sense to encourage people to purchase more reliable masks.

"In my opinion, it's unreasonable to expect that there would be studies on the effects of cloth masks."

That's fine, but there are lots of plausible interventions that have little/no evidence, and we don't mandate those by law. Why this one?

For example, the Lancet study commissioned by the WHO found that eye protection is about as supported by the available literature as surgical masks. Why aren't we all required to wear goggles?

I believe that "science" should not be used to mandate actions that have no scientific data backing them.

"it probably makes more sense to encourage people to purchase more reliable masks."

The issue there is still shortages. I don't buy surgical or n95 masks, because other people need them more than I do.

> For example, the Lancet study commissioned by the WHO found that eye protection is about as supported by the available literature as surgical masks. Why aren't we all required to wear goggles?

Because masks are being recommended to work on outgoing virus. Unless you've evidence respiratory viruses spread significantly via jets of air emitted via your eyeballs, this is a weird argument.

"because masks are being recommended to work on outgoing virus. Unless you've evidence respiratory viruses spread significantly via jets of air emitted via your eyeballs, this is a weird argument."

If you read the Lancet paper, you'll find that they pooled papers for source control and PPE together to arrive at their conclusions. In fact, most of the papers they used in that meta-analysis were for surgical masks used as PPE (personal protective equipment) in a medical setting.

In other words, the advocates for masking are doing the same thing that you're saying is weird. If you try to break the analysis down according to specific lines of evidence (i.e. source control for the public), you quickly find that there's not enough data to draw any conclusion.

On the other hand, the argument in favor of this kind of pooling is straightforward: if your end goal is to reduce transmission of a virus, and you find that goggles are highly effective at preventing infection, then it doesn't matter very much. Tell everyone to wear goggles instead, and forget about the masks. Transmission will still be reduced.

Medical settings are concerned largely with PPE that protects the staff, and a number of healthcare procedures are aerosol-generating.

Mask wearing for COVID is targeted at reducing likelihood of spreading to someone else.

> If you try to break the analysis down according to specific lines of evidence (i.e. source control for the public), you quickly find that there's not enough data to draw any conclusion.

We're going to get a lot of data soon, but for the time being, it's probably best to err on the side of "something that stops droplets probably helps stop a disease spread by droplets".

We already have lots of data. Here's the Lancet paper: https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

> Our search identified 172 observational studies across 16 countries and six continents, with no randomised controlled trials and 44 relevant comparative studies in health-care and non-health-care settings (n=25 697 patients). Transmission of viruses was lower with physical distancing of 1 m or more, compared with a distance of less than 1 m (n=10 736, pooled adjusted odds ratio [aOR] 0·18, 95% CI 0·09 to 0·38; risk difference [RD] −10·2%, 95% CI −11·5 to −7·5; moderate certainty); protection was increased as distance was lengthened (change in relative risk [RR] 2·02 per m; pinteraction=0·041; moderate certainty). Face mask use could result in a large reduction in risk of infection (n=2647; aOR 0·15, 95% CI 0·07 to 0·34, RD −14·3%, −15·9 to −10·7; low certainty), with stronger associations with N95 or similar respirators compared with disposable surgical masks or similar (eg, reusable 12–16-layer cotton masks; pinteraction=0·090; posterior probability >95%, low certainty). Eye protection also was associated with less infection (n=3713; aOR 0·22, 95% CI 0·12 to 0·39, RD −10·6%, 95% CI −12·5 to −7·7; low certainty). Unadjusted studies and subgroup and sensitivity analyses showed similar findings.

The important bit here (for everyone saying we have great evidence that masks work) is that "low certainty" bit. That's GRADE, and it means "low certainty (our confidence in the effect estimate is limited; the true effect could be substantially different from the estimate of the effect);" So, maybe masks are substantially less, or more, protective.

Like I said, I'm not doing the dance again.

Last time it was pointed out "low certainty" doesn't mean what you imply it does (https://news.ycombinator.com/item?id=23434344) you let it sail on by.

Here's what low certainty grade results mean: "low certainty (our confidence in the effect estimate is limited; the true effect could be substantially different from the estimate of the effect);".

Just so we're clear: you've never linked to research to support any of your points, because you're not able to, are you?

> Just so we're clear: you've never linked to research to support any of your points, because you're not able to, are you?

I did. 28 days ago.

https://news.ycombinator.com/item?id=23434255

https://news.ycombinator.com/item?id=23434053

> Here's what low certainty grade results mean: "low certainty (our confidence in the effect estimate is limited; the true effect could be substantially different from the estimate of the effect);".

You're acting like its definition is "it's probably the opposite, and thus is evidence for my argument".

And last time you posted those links I pointed out that they were for the same paper and the paper doesn't support your point.

Here's someone explaining what GRADE means:

https://twitter.com/dnunan79/status/1269014574478626819

"I teach GRADE

If something has “low quality” evidence, it means the observed estimate is highly likely to be different from the truth.

Face masks = low quality evidence.

So what’s the point of GRADE if we can conclude “evidence shows”?"

EDIT: Your link even says this

> Further high-quality research, including randomised trials of the optimum physical distance and the effectiveness of different types of masks in the general population and for health-care workers' protection, is urgently needed

The way things have played out in countries that instituted near universal mask wearing is sufficient evidence to start doing it. Evidence doesn't have to be peer reviewed and published in a scientific journal to be useful.

Where has science been since quarantine started? Everything is heavily politicized, there's no shortage of bizarro faux-factual evidence for all kinds of nonsense. Someone sent me an article today about the _dangers_ of wearing a mask.

I agree that the rush to penalize people is unfortunate. On the other hand, I'm not sure what we can do (short of a national response) that would be more effective. Making these kinds of policy decisions strikes me as pretty out there for your town council person or even a state level legislator.

Agreed. Pointing out that there's not much data supporting masks has become so political that you get downvoted just for saying it. I've been dismayed by the number of scientists I know who seem to have given up their skepticism on the topic.

If we can't have a rational scientific discussion about facts, we're back to the dark ages.

> If we can't have a rational scientific discussion about facts, we're back to the dark ages.

We're rapidly heading that way. Masks are a political discussion now, not a scientific one. Most other aspects of COVID are the same way. You cannot criticize anything non-politically these days. Even saying "this data is entirely inconclusive" or "the first-order effects of doing this are positive but there are negative second-order effects" is a problem.

I don't have a solution, but I feel your pain.

Before the spread of disposable masks (a few dozens of years back), the masks were made of cloth. Look at the pictures from the 1918 fever for example. I guess studies were made, it would be interesting to know what people thought.

This brings up an interesting question: why are people around the world still being encouraged/mandated to use cloth masks (whatever their efficacy)?

Surely manufacturers and supply chains for conventional masks have caught up with the demand by now?

"Masks" covers various types of respirator (such as N95 or FFP3), and fluid-resistant surgical mask, and surgical masks that are not fluid resistant.

We have lots of evidence for all of these, and most of that evidence doesn't show any benefit for surgical masks that are not fluid resistant.

I fully support your critical thinking about masks.

There's conclusive evidence that masks help on a micro level by stopping droplets.

It's possible that masks also increase aggregate infection rate by requiring a population uneducated in mask usage to apply a potential plague vector directly to their faces.

It will be shocking if science does come back in the future and indicates that mask usage reduces the chance of spreading covid BUT INCREASES ones chance of contracting it.

Mask usage is important and many people don't know how to use a mask properly. If someone puts a cloth mask on backwards they're inhaling a virus that stays on surfaces for days.

Masks may also increase the chance of infection by causing people to put their hands near their face more often to adjust or don the mask.

Even in the most recent World Health Organization report:

"At the present time, the widespread use of masks by healthy people in the community setting is not yet supported by high quality or direct scientific evidence and there are potential benefits and harms to consider "

Additionally Sweden had no mask laws and its infection rate has stabilized while place with mask laws like Cali and Washington have skyrocketing rates of infection.

Masks have become a religious war and most people accept it without question and have never looked a single shred of research from legitimate sources that aren't news media based.

I personally think it gives people the feeling of power over a powerless situation.

I just hate to see laws forcing people to do something backed by weak science and I hope this isn't like Thalidomide or Lead paint where experts validated something based on weak science that turned out to be wrong.

> It's possible that masks also increase aggregate infection rate by requiring a population uneducated in mask usage to apply a potential plague vector directly to their faces.

If there's SARS-CoV-2 on your mask, there'd be SARS-CoV-2 on your unmasked face if you weren't wearing one. Right?

Osterholm's claims are not supported by the evidence. He claims to respect aerosol scientists, but doesn't have any on his team and none have been involved in his team's work on this issue. He claims that people that are experts in modeling have not modeled correctly, despite having no familiarity with modeling.

On the other hand, our paper includes one of the world's top aerosol scientists, along with top epidemiologists, biostatisticians, and other experts. https://www.preprints.org/manuscript/202004.0203/v2

The rubbish spouted by CIDRAP about masks is very obviously flawed, as you can see for example here: https://www.fast.ai/2020/04/20/skeptics-masks/#what-about-th...

Osterholm has never written any paper about community mask wearing. He is not an informed authority on this issue. The efficacy of masks has now been very clearly shown in multiple studies, e.g:

https://gh.bmj.com/content/5/5/e002794

https://www.thelancet.com/journals/lanpub/article/PIIS2468-2...

https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818

Your lancet article has one mention of the word "mask", and says this:

> We are also unable to explicitly decompose physical distancing measures into constituent components, such as staying 2 m apart, increased hand washing, and face mask wearing, as the relative effectiveness of these components has not yet been estimated.

Did you post the right link?

DanBC is correct: why is he being downvoted?

"Osterholm has never written any paper about community mask wearing. He is not an informed authority on this issue"

And neither are you. Your "paper" on the subject is a joke. I've read it, and I've read the source literature you cite. It is a series of sloppy misinterpretations and mis-representations of the other papers, coupled with the results of running an ad hoc epidemiological model with questionable parameters. It is a quora post, written up like a paper, and pushed to a pre-print server.

You cite papers that are rated by Cochrane (and others) as low-quality, as if they are reliable evidence. You dismiss papers that do not support your conclusions for "lack of evidence", but deflect similar criticisms of your own conclusions with "absence of evidence is not evidence of absence". Quite simply: your analysis wouldn't pass muster at even a third-rate journal, and Osterholm has rightly called you out on it.

It's especially ironic that you say that Osterholm is not an "informed authority" -- he leads one of the country's leading research institutes on infectious disease, has a long history in epidemiology and public health, and spends the better part of an hour-long podcast specifically describing his experience and outlining areas where he has no specific expertise. Say what you want about the man, but he is rigorously honest about his experience. Yet I regularly see you cited as a "mask expert". Where did you do your research, again? Was it when you were getting a philosophy degree, or when you were at Fastmail? Maybe Kaggle has a mask competition?

As for the papers you've cited here: the first link you cite can't separate the effects of social distancing, gloves, masks, and other interventions, and finds mainly that people who take precautions against infection have better outcomes than those who don't. When they actually try to break out masks, specifically, they find that they don't have any effect after illness onset, which should make you doubt legitimacy of the results.

The second link provides no evidence for masks. It is a modeling study.

The third link has the same problem as the first, but worse: it can't possibly separate the effect of masks from everything else that was happening in the examined states at the same time. There is no control.

Thanks for sharing that article - I wrote it months ago, and there's been plenty more papers that have come out since, but there's really not much I'd change in it today. The science has only become more clear.

I think the 538 article really under-states the evidence. I'm quoted in it, but only about my thoughts on the political situation. I actually pointed out to the author that the science is stronger than any other intervention we have.

So you're Jeremy Howard? Hi. Someone on this thread recommended this article by yourself, on The Conversation, that I managed to miss a couple of months ago (I can't find again the post where the link to the article was given, apologies):

https://theconversation.com/masks-help-stop-the-spread-of-co...

From what I can see in the article, you were first convinced that masks should be worn after watching a youtube video. Then, having been convinced by the video you found more evidence to support your conviction.

I quote from the article:

The research that first convinced me was a laser light-scattering experiment. Researchers from the National Institutes of Health used lasers to illuminate and count how many droplets of saliva were flung into the air by a person talking with and without a face mask. The paper was only recently published officially, but I saw a YouTube video showing the experiment in early March. The results are shockingly obvious in the video.

I have to say, this rings all manner of alarm bells. For example, a video on youtube cannot be seen as evidence of anything, even if it's from the NIH; that video could at best be seen as evidence of a likely mechanism for the spread of the virus, but evidence of a mechanism that could produce an effect is not evidence that the mechanism produces that effect; etc. In short, all this is not "strong science", even if it led to strong convictions.

In any case, we all have to remember -data scientists first of all- that "data science" is not a "science" in the sense that e.g. epidemiology is a science and in a time of a public health crisis, the stage should be left clear for the relevant experts.

https://medium.com/p/4ef05aa357c5?source=linkShare-72308c464...

The "science" of mask wearing is plagued by redundant and irrelevant abstract mathematical concepts.

A mask is a membrane (not perfect, of course) and this is how it must be properly modelled.

It is that simple - just use proper (right) abstractions.

All the sophisticated statistical extrapolations is just flawed bullshit.

I just want to point out all the people who say "It's about protecting others, not yourself" or some variation are part of the problem! That can be said about the random diy cloth masks, but for everything else:

The science of masks hasn't changed...

N95 – Filters at least 95% of airborne particles. Not resistant to oil.

Surgical N95 – A NIOSH-approved N95 respirator that has also been cleared by the Food and Drug Administration (FDA) as a surgical mask.

N99 – Filters at least 99% of airborne particles. Not resistant to oil.

N100 – Filters at least 99.97% of airborne particles. Not resistant to oil.

R95 – Filters at least 95% of airborne particles. Somewhat resistant to oil.

P95 – Filters at least 95% of airborne particles. Strongly resistant to oil.

P99 – Filters at least 99% of airborne particles. Strongly resistant to oil.

P100 – Filters at least 99.97% of airborne particles. Strongly resistant to oil.

I've been wearing a p100 respirator that makes a good seal to protect myself, and been changing out a small piece of cloth on the out-valve to protect others. Please, stop perpetuating the myth that masks don't protect you. Of note is that while many of the higher rated masks tend to be tested at .3 microns, this is often a buffer and real world they tend to filter about .1... and the virus is said to be .12+ micron.

So if you can, I would suggest getting your hands on n100 or p100, preferable use an oximeter to make sure you have the physical fitness needed to force the air through, but if you are doing very small timeframe adventures this becomes less of an issue. Something that makes a good seal is ideal. Guys, you should heavily consider shaving. There is a reason in the military NBC training they started requiring with only a few exceptions, shaves... and no, the military gas masks will not work for this application unless you get the specific filters for this application (if you do, they would be great since they integrate the eyepro), which have a much wider ranger to select from than the above I reference...

note: it is also very important to verify you haven't been sold a fake product

https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part...

Airflow follows the path of least resistance. Air and the particles in it will go around the edges of the mask where there is zero resistance.

Even this is an improvement. After flowing around the edge it is moving at a lower speed and so particles will travel a smaller distance.

It also means the droplets are mostly separating back out onto your skin, and also are not being directly blown into everyone elses face.

We're talking personal protection at the moment. It's clear it's tops droplets from affecting other people. But it provides zero personal protection.

Not jf the pressure is ever so slightly increased.

Proper masks seal tightly to your face, there is no edge to go around.

Note that facial hair can prevent that.

Have you ever used an n95 mask? They have a rubber band but that's it. I've always gotten stuff inside my mask any time I've used it for painting or carpentry.

Quite often, at least back when they were available for industrial use. I prefer to use non-disposable p100 masks with a silicone seal. The seal leaves a red mark on your face after a few hours but it’s worth it to not inspirate hazardous materials if your mask gets bumped.

That said, N95 masks can work fine if you fit them properly, which may involve shaving any facial hair outside of a mustache, shortening the rubber straps, or adjusting the metal nose bracket.

It’s worth noting that an n95 mask doesn’t really provide vapor protection so it may not do too much for you while you’re painting but if you’re getting wood dust inside then your mask was either improperly fitted or it’s the wrong size for your face.

No they can't.

Do you mean that n95 masks can't work fine? If so, I'm genuinely curious as to how they failed for you.

I've used them while working on-site at a coal mine, as long as you're using a genuine high quality n95 mask and have it properly fitted you can absolutely wear one for 4+ hours without the inside getting contaminated. It's certainly not fun but I've done it many times without issues.

I think that the whole "masks don't protect you they protect others" spiel was designed to save face, because authorities were adamant about masks not working until March. Of course they protect the wearer....otherwise healthcare workers wouldn't use them.

I'm pretty sure health care workers wear them primarily to protect others. This is what my health care worker friends have told me (long before covid). Sneezing on someone mid surgery would be pretty bad for the patient, not really for the surgeon.

I think the reason people say it's more for others than yourself is because it's actual pretty rare to catch a disease by breathing it in. Much more often you catch it when it gets on your fingers and then you touch your eyes/nose/mouth. I think that's still at least partially true with covid.

Properly fit N95+ masks definitely protect the wearer, but in clinical settings are also combined with measures like a faceshield (which reduces droplet exposure to the eyes specifically, and reduces possible viral load on the face generally).

Conversely: pretty much all masks (though ones with an exhalation valve will reduce the effectiveness) will reduce the spread of droplets and thus virus from exhalation and talking: https://www.youtube.com/watch?v=kYJvU81DKgk

But the WHO said masks don't protect you? Who am I to believe, the World Health Organization, or some commenter on the internet? Just trust the health experts dude and stop being such a science denier. /s

Where did you purchase N100 or P100 masks from?

I happened to already have two masks and quite a few filters in stock from a painting project before all this started... home depot or lowes I think. They are probably hard to come by, but maybe not because I don't see many people wearing them. I got weird looks at first, and heard people making fun of me quietly, but that mostly stopped the longer this all went on.

Reply on news.ycombinator.com