Surgical masks reduce Covid-19 spread, large-scale Stanford study shows | Hacker News Reader

Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

med.stanford.edu

152 pointsdjrogers228 comments

> There were significantly fewer COVID-19 cases in villages with surgical masks compared with the control villages. (Although there were also fewer COVID-19 cases in villages with cloth masks as compared to control villages, the difference was not statistically significant.) This aligns with lab tests showing that surgical masks have better filtration than cloth masks. However, cloth masks did reduce the overall likelihood of experiencing symptoms of respiratory illness during the study period.

I think this is probably the most interesting part, and worth watching in future studies.

It's surprising to me that cloth masks can't even do the 11% of surgical masks. Which isn't much, but surgical masks are non-optimal for many reasons. Not to mention that this doesn't seem the same as "while wearing a surgical mask you only get 11% increase in protection" but is a population-level thing. There was still non-compliance that presumably lowered the efficacy. I would've intuitively guessed that the better fit of cloth masks would make them better, but presumably the mask surface of a surgical mask has properties that offset that?

Would be great to see numbers for N95 masks. Intuitively I'd assume they'd be much more effective as they have better fit + higher filtration, but of course, confirmation would be great.

Fits with what we're seeing in Europe such as airlines banning cloth masks, though.

The great incoherent idiocy of anti-* Americans on the issue of masks has always been that they say "cloth masks are ineffective" and propose a solution of "do nothing" instead of "get effective masks."

>It's surprising to me that cloth masks can't even do the 11% of surgical masks.

Just want to add clarification here. The 11% number is the community impact of the programs designed to increase mask usage. It is not the effectiveness of a mask on an individual level. That number will be much higher since as you said a number of people didn't/don't comply at a societal level.

Thanks! I edited my comment to add notes on that too. At a population level even a small portion of the population wearing masks reducing overall spread is very good to see. Even for surgical masks.

> That number will be much higher since as you said a number of people didn't/don't comply at a societal level.

...or it will be lower. The study confounds the effects of distancing and mask-wearing. Distancing was higher in the surgical mask cohort. Also, as others note, the confidence interval for the surgical mask group overlaps zero. You can't rule out that the observed effect is due to chance.

yes, distancing does most of the work in most common situations. a mask can only work when conversing closely for a time indoors. otherwise masks do nothing, no matter the filtration rate of the mask, because there's nothing to filter in the first place. distancing is a more universal and sensible mitigation (we're distanced from nearly all of the world population all the time).

this is why mask mandates, as currently constructed, are misguided and ignorant at best. the mandate should be to wear a mask when you're intimately sharing air (within ~3ft/1m) with another person indoors. the reason we don't have that sort of mandate is because it would mean we'd have to wear them around friends and family rather than those gross strangers who are out to kill us with their ignorance and malice (they're not).

this is also why the current mandates for restaurants (and most retail) makes no sense, as we're only going to be intimately sharing air with our friends and family in those places anyway.

Aren't you sharing air with others in any common indoors space?

I thought that was the whole aerosols debate that's basically settled by now, i.e. virus can stay suspending in the air for extended periods. With the Delta variant's characteristics this is also a much bigger problem (i.e. the same indoor space that might have been ok is no longer ok).

There were early studies with the less infectious variants that showed how people situated far from each other in indoors spaces infect each other.

So the mandate for masking in any common indoor space seems to make a lot of sense.

no, it's not "settled science" like that. the virus must traverse a gauntlet of death before reaching your juicy mucus membranes, including dessication and all manner of external forces that will inactivate it in the meantime. it falls apart in droves outside the body. you need constant exposure to warm, moist, infected exhaust so that the virus has trillions of chances of taking hold in your respiratory system, and it likely takes millions of virus particles making it across for enough to survive the immune response gauntlet inside the body. that a few virus particles in controlled tests miraculously manage to exist for a few minutes in the air has no bearing on real-world transmission rates.

that's why a mask can work (better than distancing) in that one particular situation, but distancing is a better general mitigation.

by the way, those early "studies" on long indoor spread were conjecture-based (e.g., using models), not rigorous science, and have failed to replicate.

I'm not talking about model studies. I am talking about case studies, like: https://www.nytimes.com/2020/04/20/health/airflow-coronaviru...

Also: https://www.the-scientist.com/news-opinion/ferret-study-rein...

Even early on with the Diamond Princess you've seen wide spread of the virus despite passengers being largely confined to their cabins. There were multiple other examples.

We also know the Delta variant is more infectious.

I'm not saying distancing doesn't work. Even if you assume the virus is spread in the indoors air it's not a terrible bad assumptions to think that a person emitting virus continuously will have a higher concentration of virus in their immediate vicinity. So sure, it's layers of defense. The mask is also about limiting the emissions in the first place and distancing indoors is not always practical in public busy spaces.

But sure. It is not settled science. Science takes time. If your point is that we don't understand exactly what happens then sure, but we rarely do for anything in this field anyways.

the diamond princess is especially poor evidence, as it was an after-the-fact investigation (with heavy motivation to find something and gain early notoriety), not a study per se. what likely happened was that there were multiple social infection vectors (not of the long-distance air variety but more the drunk chatting variety) and the crew and passengers distorted their testimony to limit their own liability exposure. the diamond princess case was also the source of the "virus lives for weeks outside the body" mistruth because pcr tests readily amplify partial, dead viral dna/rna just as well as live virus (it has to be 'killed' to be amplified, after all).

but yes, viral concentration is higher near an infected person, but it falls off rapidly (to something like the 3rd power iirc) with distance and time, especially the latter of which being why incidental exposure in public places is unlikely to be material. it's also something a small minority of people have at a given time (on average less than 1% of those around you). it's mainly socializing for extended periods of time where masks can potentially help reduce infection (that's when we're also most likely to let our guard down).

i'd go so far as to posit that sociability (via variables like social graph size/breadth) is likely more correlated to infection than (the lack of) mask usage.

The diamond princess people also ate their meals in a shared space, IIRC. I think they changed that eventually, but by the time they did, the conclusion was hopelessly confounded.

From the study:

>The intervention increased proper mask-wearing from 13.3% in control villages (N=806,547 observations) to 42.3% in treatment villages (N=797,715 observations)... Physical distancing increased from 24.1% in control villages to 29.2% in treatment villages

Mask wearing increased 218% while distancing increased by 21%. I agree this is not proof specifically about masks, the study is about specific public policy programs and not mask wearing in general, but it certainly seems like masks wearing is the biggest contributor to the reduction seen.

I think it's also important to note that there was no change in physical distancing seen in indoor environments (mosques) - maybe due to the fact that it's obviously easier to spread out when outdoors. I think we are fairly confident by now that the vast majority of spread occurs indoors [1].

[1] https://academic.oup.com/jid/article/223/4/550/6009483

> Mask wearing increased 218% while distancing increased by 21%.

You can't just compare "percentage change" of two wildly different things, and leap to the conclusion that the magnitude of change is causal. It begs the entire question: if physical distancing works well, and mask wearing does not work, you could increase mask wearing by whatever percentage you like, and a smaller change in physical distancing would still overwhelm it. We don't know.

But aside from that, you skipped over an important part of what I said: distancing was higher in the surgical mask group. See Table 2.

> It begs the entire question: if physical distancing works well, and mask wearing does not work (...)

There's nothing in the study remotely suggesting that masks have no effect. Instead the study shows that mask wearing combined with other factors have a clear and unquestionable correlation with reduce Covid spread.

Even if you wish to nitpick the contribution of mask wearing in the reduction in Covid spread, it makes absolutely no sense at all to jump to the conclusion that surgical masks have no impact in spreading airborne pathogens as that's precisely what surgical masks do and the whole reason why they are extensively used by the medical community for decades.

> Instead the study shows that mask wearing combined with other factors have a clear and unquestionable correlation with reduce Covid spread.

The study shows that cloth masks (combined with other factors) have no effect on seroprevalence. It shows that surgical masks (combined with other factors) has a small-but-significant effect on seroprevalence. The confidence interval on the surgical mask group overlaps zero, so you can't rule out "no effect". At these small effect sizes, you also can't rule out the role of confounders -- it's possible that behavior change could explain all of it.

In short, neither result is "clear and unquestionable". An accurate description of the results are that they are "weak and debatable".

> The study shows that cloth masks (combined with other factors) have no effect on seroprevalence.

No, not really. If you happen to take a few minutes to read the paper, you'll notice that the study was conducted with a type of cloth mask produced locally which had a filtration efficiency rate of around 37% with a standard deviation of 6%, compared with the surgical mask's filtration efficiency of 95%.

The study also points out that the filtration efficiency of surgical masks washed 10 times with soap was 76%, and that they evaluated a type of cloth mask which can achieve a filtration efficiency of 60%.

Thus, what the study actually states is that they observed that wearing poor quality cloth masks showed high-variance results whose confidence interval includes the point estimate for surgical masks.

In other words, the study actually pointed out that using a specific type of cloth mask produced locally and which was known to have poor filtering efficiency had an effect that lies somewhere between being as good as surgical masks and not wearing anything at all.

> The confidence interval on the surgical mask group overlaps zero, so you can't rule out "no effect".

No, not really. That's not how confidence intervals work. At most, the only conclusion you can objectively draw from the data is that even though the positive effect of wearing surgical masks in the past study is clear and beyond doubt, further studies would be required to increase the resolution of that estimate.

In fact, if you happen to read the study you'll notice that the conclution states quite clearly that "We found clear evidence that surgical masks are effective in reducing symptomatic seropreva- lence of SARS-CoV-2; while cloth masks clearly reduce symptoms, we cannot reject that they have zero or only a small impact on symptomatic SARS-CoV-2 infections (perhaps reducing symptoms of other respiratory diseases)."

Also, your comments feel like a mix of moving the goalpost combined with a considerable amount of cherry-picking. It's a widely known fact that the whole point of wearing masks is primarily to reduce the viral load emitted by the wearer, and a minor benefit is to reduce our own exposure to the virus. Thus I feel that you're trying to misrepresent the whole point of wearing masks by trying to frame it as a "seroprevalence" issue. That was never, at any point in time, the reason why we have the social obligation to wear face masks and respect social distancing.

> If you happen to take a few minutes to read the paper, you'll notice that the study was conducted with a type of cloth mask produced locally which had a filtration efficiency rate of around 37% with a standard deviation of 6%, compared with the surgical mask's filtration efficiency of 95%.

I read it, thanks. The mask they used was much better than what most people are wearing:

> The cloth mask had an exterior layer of 100% non-woven polypropylene (70 grams/square meter [gsm]), two interior layers of 60% cotton / 40% polyester interlocking knit (190 gsm), an elastic loop that goes around the head above and below the ears, and a nose bridge

If a cloth mask with three layers of different materials and a nose bridge is dramatically less efficient than a simple surgical mask, then that's pretty damning for the whole idea of a cloth mask, in general.

> I read it, thanks. The mask they used was much better than what most people are wearing.

Can you give a citation for that? I think you might be in a strange place. Here nearly everybody wears surgical masks, most people were 2 : a surgical and cloth mask.

Also I'm interested in an experimental design or study design you would find acceptable. I saw your comments now on 3 papers showing evidence for mask wearing. It seems you are moving goal posts ever time.

Given a really effective intervention for a contagious disease, the effectiveness on a community level will be much lower on an individual level. Think about PRC vs. USA: 4636 deaths in PRC, 618591 deaths in USA, even though it's a four times smaller country. There is no measure that even comes close to reducing your risk of death from covid by a factor of 600 on an individual level, but because they were able to get the R number down below 1, they stopped the epidemic.

Normally you would expect effective contagion control measures to have an exponentially larger effect at a societal level than it does at an individual level, even if you don't reach the critical threshold to stop the epidemic: if you can drop R from 2.0 to 1.9, that reduces your individual risk by 5%, but it also reduces the number of cases in the next generation by 5%, the number of cases in the generation after that by 10%, the number of cases in the generation after that by 14%, etc. After 20 generations of transmission you've reduced the number of cases by 64%, which reduces everyone's infection risk by 64%. Of course, with such a high exponential growth rate, that only means that people get infected 1.6 generations later at that point, but if you're comparing different communities at the same time, the difference is about 3:1.

So it seems like probably the effectiveness of the mask on an individual level was truly tiny.

> Think about PRC vs. USA: 4636 deaths in PRC, 618591 deaths in USA, even though it's a four times smaller country.

4636 deaths as reported by the CCP to foreign journalists. Same party whose official line is that nothing happened in Tiananmen Square.

This is nonsense, partisan propaganda masquerading as rational thought. Nevertheless, there are many countries that had similarly effective infection control, so even if you choose to believe your hate for China instead of the best unbiased assessments, check out New Zealand, Vietnam, ROC, Thailand, or Australia.

> 4636 deaths in PRC

That number is completely laughable. It's literally communist propaganda.

I have no particular insight into that particular number, but it isn't believable that covid has been broadly circulating in China uncontrolled for the past two years, and there isn't much middle ground between "uncontrolled spread" and the media-reported state of affairs.

I come to HN for intelligent discussion, not xenophobic conspiracy theories so far-fetched no intelligent person could believe in them.

>Normally you would expect effective contagion control measures to have an exponentially larger effect at a societal level than it does at an individual level

Isn't this dependent on the assumption that the risks are reduced uniformly across society? Lockdowns/quarantines are the obvious counterexample. Someone going into complete lockdown reduces their risk to practically zero. However a small group of people doing that won't have much effect on the societal numbers. Therefore the societal reduction is much less than the individual reduction until that R value drops low enough.

I think most of us got cloth masks with the full expectation that they were worse than proper PPE from hospitals (be it surgical masks or N95 masks).

I'm not sure if people remember: but there was a shortage of masks of all kinds in March 2020. Cloth masks were the only thing we could get, and we all knew they were kind of crap (a lot of us were using coffee filters stapled onto the masks to increase its effectiveness).

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Now that the N95 shortage is over (at least, I'm buying N95 duckbills at $1 each these days), I think its time to seriously consider using N95 in the public. At least in America, where we seem to have suddenly a huge influx of N95 availability this year.

Seems quite reasonable to wear a (K)N95 instead of a surgical mask. Slightly less comfortable, but yes, affordable for most.

That "K" means that my ears hurt after 2 hours though.

Going for full N95 means that the strap goes all the way around my head and is way more comfortable for extended use (ex: airplane rides or whatnot)

There are also KN95 masks with headband straps instead of earloop straps. E.g., a web search for "Powecom KN95 Respirator Headband Style".

Also 3M 9502+ KN95 which was subsequently NIOSH N95 approved (but you had to pay more if you wanted the ones stamped for the US market).

There are "ear savers" you can get that'll turn the ear loops to headbands.

I'll admit I've tried the plastic & velcro ones and didn't like them - but I also don't wear them for hours at a time but just for quick trips so found them annoying to put on and off.

"Slightly", I'm not so sure about that :-D

Where I live, N95 masks are mandatory in public transport since February, and it's really uncomfortable to be in an non-airconditioned metro car which is full to the brim, with water running down the windows from condensation. That's totally acceptable with surgical masks, but there's a face melting heat under any N95 mask in this condition :-D

Of course I wear them as mandated, but I really hope we can switch back to the more practical surgical masks soon, with enough vaccinations :-)

(Or that there is an early onset of winter :-D)

Could you share a link for $1 N95's? That's better than I've seen. I've already moved to this approach myself, it's an increase in cost that I'll gladly take for increased protection. Just waiting for government and businesses in the US to catch up.

It was definitely hard to find the good stuff at first - and I was much more reclusive as a result too - but yeah, things have changed.

I wish people wouldn't respond to changes in policy/advice as evidence of "lying" before, as much of it has just been learning more. (Though the "we're gonna tell people they're ineffective because we want to reserve them for professionals" thing was a huge unforced error, IMO.)

So $1 masks are only "Duckbill" masks, which look kind of stupid. But they're clearly low cost and have very high surface area / breathability. Also, real N95, so major benefit for sure.

https://accumed.com/30-pack-fda-cleared-niosh-n95-surgical-r...

These straps kinda suck though. I recommend carrying a few extras somewhere since the straps may snap throughout the day. I'm still looking for a better mask. For all of its faults, this one is available today and at the promised $1 price too.

The BNX duckbill masks used to be $1 per. But they seem sold out. Keep an eye on them just in case they come back into stock. https://bnx.com/products/bnx-50-pack-n95-mask-respirator-nio...

The Kimtech 53358 Duckbill WAS $1 each just a month ago. But their prices suddenly skyrocketed to $1.50ish from most sources. EDIT: If you buy 300 of them, you should get close to the $1/each price, but I want to "test" them before dropping $300 buckaroos on it...

EDIT: WB Mason is selling the Kimtech Duckbills at $50 per 50-pack, so that's $1 each: https://www.wbmason.com/ProductDetail.aspx?ItemDesc=Kimtech-...

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I'm not sure how much I trust Amazon's supply chain for proper N95 / NIOSH approved products. A lot of Amazon's stuff are 3rd party shippers and/or 3rd party suppliers instead of official sources, and comingling is an issue.

If its $1.50 from a proper medical store, then the $0.80 price at Amazon is probably too good to be true. If we're paying extra for the N95 rating, I'm willing to pay extra for proper supply chain.

You can get the awesome 3M Aura used in hospitals for $2.20. These are great: https://www.ebay.com/itm/224332977653?_trkparms=amclksrc%3DI...

I keep reading this as >You can get the awesome 3M Aura used

Costco "non-duckbill" N95 are $1.50 currently. They have the duckbill/fold-flat N95-ish kind for $0.60.

We recently got a set of those for Back to School, and have been fairly happy with them. Previously we had gotten from, IIRC, "maskhq" which had a comment reply ~18 months ago from the guy running it, the big thing there was authenticity traceable back to factory. They were ~$1ea. Can't seem to find the site now, maybe it has gone away.

https://www.homedepot.com/p/3M-N95-Particulate-Performance-D...

Home Depot sells this 20 pack for $24 from 3M. That’s $1.20 each.

Incidentally, if you buy 3M masks, there's a number on the bottom of the box that can be validated on 3M's web site.[1] They will tell you if that's a valid number and if anyone tried to validate that number before.

[1] https://safeguard.3m.com/Guest#/Validation

Count your masks. My box of 10 3M masks (closed not taped shut) from Home depot only had 9 in it.

The told me I can gladly travel 30 min back to the store and wait in line for a refund. No thanks.

What about the amount of waste/garbage this creates? It's already a problem finding random discarded masks all over the place. We need a reusable/washable N95 class mask.

> The great incoherent idiocy of anti-* Americans on the issue of masks has always been that they say "cloth masks are ineffective" and propose a solution of "do nothing" instead of "get effective masks."

I think the "no nothing" solution has more to do with a desire to return to normal than it is a refusal to "get effective masks" and just wear them forever or until some agency says not to anymore. There is a valid point to be made that once you're vaccinated and most people around you are vaccinated it's time to start learning to live with the reality of covid being a mild disease you get once in a while. I suppose a masked up future is one of better public health for some, but for many it is psychologically exhausting to see your friends and coworkers as potentially dangerous vectors of contamination. This is especially dystopian when the government forces you to do this whether it's sensible or not.

Wearing a proper mask that actually substantially reduces the chance of contracting or spreading covid is uncomfortable. As many of us have been saying from the beginning (including the CDC initially!) the cloth masks are just the medical equivalent of TSA security theater. Right now they just function as a little badge to indicate which "team" you're on.

I cannot understand why this is being downvoted. We would have all been wearing N95's long ago if they weren't difficult for frontline workers to use 8 hours a day. People care about their own health by and large. They will use reasonable strategies for mitigation and reject those that are cumbersome.

The people pushing N95 mask requirements are not the same people required to wear them 40 hours a week. The people pushing non-N95 mask requirements are confused about the effectiveness of non-N95 "masks".

I mostly agree. The problem is mostly with populations that have a large number of un-vaccinated people. If we could separate those unvaccinated people from the vaccinated people then the vaccinated people could go back to normal and I agree the impact is probably small (not quite sure about "mild disease you get once in a while" but something we could live with). However when you have a 50/50 mix of people who have mild disease you get in a while and people who get a serious disease that leads to hospitalizations and death at a relatively high rate you now have a problem. And it's a problem for the vaccinated 50% who would not be able to get into the hospital when they have a medical emergency, or can't get their scheduled medial procedure done, or bearing the costs associated with those other 50%, or even just having a higher likelihood of getting sick with something they obviously prefer not to get (mild or not).

So the governments are optimizing for this (forcing us to do X) ... not for the individual but for public health and public (general) concerns. Just like they're forcing us (and fining us, darn!) not to drive through red lights, or exceed the speed limit. Are they always doing a great job? nope, but hey we voted for those guys (at least in functioning democracies)...

So here we are.

> Intuitively I'd assume they'd be much more effective as they have better fit + higher filtration, but of course, confirmation would be great.

I think that is really hard to say.

IF they are properly fitted (that won't normally be the case).

As I see it (as well intuitively) if the virus is transmitted "directly" by droplets then cloth, surgical or N95 won't make much difference from a clear plastic shield (as we have seen many in hospitals wear, besides the masks), while if it is transmitted by aerosol the filtration capacity changes matters greatly.

Point is whether a (poorly) fitted N95 does actually protect more than a surgical mask.

Since a N95 is "harder" to breath in (as it filters much more), it is possible that a lot more non-filtered air comes from the (poor) fitting gaps.

In my personal case I have (now) a beard and #1 lesson when years ago I was taught how to wear a N95 (actually a FPP2, almost the same as N95) was that you had to be cleanly shaven, and - besides that - I had to try some 5 or 6 different mask models before finding a suitable one (the mask shape need to be suited to your face shape for a proper fit).

This is a pet-peeve of mine, but noone actually wears N95 masks properly: https://news.ycombinator.com/item?id=22728367 https://news.ycombinator.com/item?id=23957506

I'm just as surprised. I used to wear a cloth mask and switched to an n95. When I tried the surgical mask I was amazed at how poorly the thing fit along the cheeks and how hard it was to form a tight fit on the nose that wouldn't loosen immediately. Breathing through it offered no resistance at all, in contrast to your typical cloth or n95 that hug all sides of the mask pretty well to your face. I thought this was because surgical masks are meant to block flecks of spit off your tongue when asking for surgical tools, rather than aerosols from exhaling. Most people I see wearing surgical masks just put them over their ears and have it loosely covering the face, with large gaps along the sides and especially around the nose.

I have been surprised a few times when wearing a surgical mask looped around my ears, when i had to remove it and then became instantly aware of all the smells of a place I was in. They were definitely isolating me from airborne particles.

"Cloth masks" can mean anything.

I wish early in the pandemic someone would have made some piece of equipment to asses whether a given cloth mask is good or not. Most people have a few now and I'm sure they would like to use the best one.

> "Cloth masks" can mean anything [...]

I guess the point is "not certified".

we could have argued for all masks being sold to post some measurable stat about the mask, but then others would have argued that would have prevented masks from even hitting the shelf and we'd be worse off.

In the first weeks of the pandemic when there was a shortage of surgical masks? Any cloth was better than nothing. Several months into the pandemic? Would have liked to see a program to distribute "better" masks and retire the bad ones.

At the end of the day if the reduction is 11%, even if that works (because that reduce by 11%) that is still useless in order to control the epidemic. Unless we find 10 measures like that. But what they show is probably not the same that the impact of mask mandate or an `always wear mask` at the personal level. So not much is applicable about that study. Only that mask kind of reduce covid spread

Anyone who is legitimately concerned about COVID transmission should be wearing at least a KN95 mask. It would be interesting if the study had compared effectiveness against higher performance masks and respirators.

I totally agree.

On the other hand I would like to opt out of this exercise, since I'm totally not concerned with COVID.

I know a place where workers keep having to quarantine following covid reoccurrences. Looking for a job?

Stop testing and there won't be new cases.

Because dead people don't replicate viruses well. Got it.

Only 0.6% will die (on average over all age groups). 99.4% will have an immunity for half a year.

Only 472,497,943 can die from it then. Adding on all the other impact of creating much larger pools of folks losing spouses, parents, caregivers, along with everyone else who's loss will cause lasting and life-changing harm.

And then there's long Covid. . .

So yeah, sheesh. It's hardly any worse than taking out several nations worth of people with VX.

Everyone will die. Eventually. Those over 60 sooner than those in their twenties. Neither tests nor masks will change this fact.

>Neither tests nor masks will change this fact.

According to the original article, masks do change this fact.

Please, read the article again. Masks might affect COVID-19 spread. They don't prevent people from dying eventually.

> They don't prevent people from dying eventually.

The paper does not say this. It shows an 11% reduction in spread in the group that was encouraged to wear surgical masks. Masks were not mandated, only encouraged. It also shows that 5 months after the researchers stopped encouraging mask-wearing, compliance dropped by 14%. So masks reduce the spread, and encouraging people to wear them leads to higher compliance.

social distancing, handwashing, increased ventilation, wfh, contact tracing app, venue contact tracing, vaccines, rapid testing, temperature checking

No idea if they're all ~10% effective, nor if you can just add percentages up like that... but it's not hard to list measures we can take, both individually and as a society.

You are making a number of pretty common errors: no anti-viral measure is going to be perfect, it is always going to be a layercake and an 11% improvement can make a huge difference because for one it might tip the balance from 1.05 to 0.95 which is the difference between a spreading disease and one that is on the return and because these percentages are multiplicative, not additive, so it would not take '10 measures like that'.

I didn't come up to the number 10 because 10 * 11% is about 100%. its just a random guess about small impact measure

We know that R of covid in a naive environment is probably more than 4. So any group of measure that dont reduce it 1 is not going to be enough. There is no 1.05 in reality for covid. When you are at 1.05 it is already because of group of measures are in place

> When you are at 1.05 it is already because of group of measures are in place

Ah and here I was thinking you thought those weren't effective. Ok, sorry.

The Delta variant R0 is in the 6-7 range.

https://www.npr.org/sections/goatsandsoda/2021/08/11/1026190...

There is no plausible way to bring it below 1 for an extended period of time. The most we can do is slow it down a little.

You are mistaken about what R0 means. It is a compound number that describes a virus and its ability to spread from person to person in a community, with all the measures (or lack thereof) including vaccinations in place.

The 6-7 range would be in a theoretical environment where nobody is vaccinated, there are absolutely no countermeasures and the number of opportunities to spread is equivalent to the pre-COVID days. Obviously, we do not live in that world.

In short, R0 is not a property of a particular virus strain but of the sum total of virus + all factors relating to population, behavior etc.

It is also best determined afterwards the way it is being treated right now as though it is some kind of input variable which can be controlled for is fundamentally wrong.

I understand what R0 means perfectly well. Vaccination and other factors can reduce it from the 6-7 level to something a bit lower. But there is no plausible sum of factors that will bring it below 1 for an extended period any time soon. Most interventions are correlated, not independent, and so the sum is less than the parts.

It doesn't take 100% control to make a significant impact. Every % you take off of transmission is significant because the relationship between transmission and cases is exponential.

100% is impossible and was not the point I was making. The only things that is import is R is below or equal 1.

The relation between transmission and cases is not exponential as :

1. Cases can't go to infinity

2. R is variable, and actually changes a lot for plenty of reasons

It is not "masks → -11%" as you seem to be reading it: it's -11% after a +30% compliance.

More compliance, much increased results than that 11%.

Am I misunderstanding this from the paper: "The proportion of individuals with COVID-like symptoms was 7.62% (N=13,273) in the intervention arm and 8.62% (N=13,893)" That really seems like a pretty small overall difference in the two groups in terms of those getting infected.

Because the the compliance increase in the «intervention arm» was +30%, not "total compliance". +30% compliance → -11% infections.

FWIW, there was also an effect of mask color. It seems like a trivial detail and in a lot of ways it is, but it kinda points to compliance as a factor and, in turn, factors influencing compliance.

> The researchers enrolled nearly 350,000 people from 600 villages in rural Bangladesh

Wow. I was about to complain about "small n", but... an experiment of this size is not small at all. Congrats on the researchers on doing such a big study!

I think it is a bit cheeky of them. They promoted the usage of masks and distancing in 600 villages totalling 350,000 people and observed the results (mask wearing plus distancing) in mosques (by sampling, not by checking each individual).

I know it's easy to get cynical about "sampling" when you see a stream of studies sampling populations of millions with n = 12 and getting p values just barely considered "significant", but that's not the fault of "sampling". That's just... gathering no data, basically, or if you prefer, going through the motions of gathering data without actually doing it.

I am not arguing with the method, I only think the language of the paper is misleading to the point that the parent commenter aparently thinks they actually analysed hundred of thousands of subjects when they just extrapolated their observations to that number. It may even be right and significant but that is not my point.

I've reread the article + paper with your discussion in mind, and I agree with you. It seems misleading, and I failed to understand the study from the headline / abstract.

Its not a "bad" study per se, but its definitely entering clickbait. I'm still happy they conducted the study and presented their research.

Maybe the relevant point is that it needed to be this big to get a P-value of less than .05, since they only got .04 even with 350,000 people. This is dramatically less effectiveness than I was expecting when I was pushing for mask mandates last year, and within a few months it was obvious that masks alone weren't having the large effect I had hoped for. Now we have quantitative estimates of how small the effect was (disappointingly small) and when it worked (cloth masks had almost no effect).

When 70% of people weren't affected by the experiment (13% were wearing masks before the experiment started. 60% of people didn't wear a mask after the experiment), then of course the numbers are going to be small.

Seeing a measurable difference when the population only changed from 13% mask to 40%ish mask usage is pretty outstanding IMO.

I don't think that's correct; see https://news.ycombinator.com/item?id=28407881 for the argument in more detail.

My argument and your argument are seemingly unrelated.

That means that the full matrix of situations are available: I'm correct and you're correct. I'm correct and you're wrong. I'm wrong and you're correct, and finally I'm wrong and you're wrong.

----------

So lets just try again from the top. The study shows that an 8-week mask-awareness campaign in Bangladesh across 300 villages (+300 "control" villages 2+km away where mask-awareness did NOT happen) leads to a 29% increase in mask usage and an 11% decrease in COVID19 cases.

Is there anything wrong with this new, revised statement I made? It seems to be the big "A / B" test that everyone's wanted for mask studies.

Oh, I think we totally agree on the facts of what happened! Except that I don't think it was an 11% decrease in covid cases, but a slower increase that ended up 11% lower.

But you said it was "pretty outstanding IMO" and I think the opposite: I think it shows that an increase of 29 percentage points in mask usage had so little effect on covid risk that it could only be reliably detected with sophisticated statistics and experimental design, and even then only at a group level, not an individual level.

Size of N isn't the issue, controlling for confounding variables is.

Its interesting that the article do not mention a rather interesting finding in the study. For the age groups of < 50 years the effect was not statistically significant with the control and the mask wearing villages having similar rate of covid-19.

Why aren't masks effective to reduce the spread for that age group? The discussion part of the study don't explore it. Is the distancing behavior of people aged 50 or higher different than those below?

I would like to see further studies being done on the younger demographic in order to explain why the data is looking like it is.

Maybe lower mask adherence among younger people or different behaviors-- older people in villages might stay at home more.

if the latter is true, then wouldn't that be an indicator that masks do not, in fact, work as well as thought?

It could, or it could mean that the protective effect of surgical masks is most pronounced indoors.

Compliance.

They did report that physical distancing increased in villages that were given masks, so that may explain it. Unfortunately they didn't untangle that effect? How do we know to what degree it was the masks vs increased distancing?

> Why aren't masks effective to reduce the spread for that age group?

This is a good question and I think it is an important one since the title implies a different situation than what was actually tested.

So the 11% reduction was due to an effort to increase mask wearing compliance by means of...

> Providing free masks, informing people about the importance of covering both the mouth and nose, reminding people in-person when they were unmasked in public, and role-modeling by community leaders

It's probably not that masks are less effective on people under 50, but that the information campaign was less effective at influencing that group to wear their masks.

Also, the results are interesting:

> The observers found that just over 13% of people in the villages that received no interventions wore a mask properly, compared with more than 42% of people in the villages where each household received free masks and in-person reminders to wear them.

It seems that there is much more progress that can be made in getting people to wear masks. And we still don't know how effective 95%+ compliance will be at reducing the spread.

Finally, the report does note that villages provided with cloth masks had worse outcomes than those who were provided with surgical masks.

It not established in the study (that I can see in their findings) that people under 50 were wearing mask less than those above 50. The finding only showed that those under 50 did not benefit.

There could be any number of reason why the result of the data look like it is. If those villages are mostly small farming communities it might be that young people spend most of their time outside on the fields or herding animals while the older population spend more time inside. It might be that the older generations after a long hard working life need more active help from younger family members and can't do distancing (like in our elder care facilities). Mask has a rather good track record when people are working inside in close physical proximity to risk groups.

Since the study did not explore those question we can only speculate.

did you check that the number of counted infections in ages < 50 is enough to get statistical significance per whatever criteria in the study?

I think the limited specificity of their definition of COVID-19 means it is easier to detect effects for populations that have higher incidence.

Here is the paper (or one of them, it is not clear after so many links):

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

Bottom line: "The proportion of individuals with COVID-like symptoms was 7.62% (N=13,273) in the intervention arm and 8.62% (N=13,893) in the control arm. Blood samples were collected from N=10,952 consenting, symptomatic individuals. Adjusting for baseline covariates, the 2 intervention reduced symptomatic seroprevalence by 9.3% (adjusted prevalence ratio (aPR) = 0.91 [0.82, 1.00]; control prevalence 0.76%; treatment prevalence 0.68%). In villages randomized to surgical masks (n = 200), the relative reduction was 11.2% overall (aPR = 0.89 [0.78, 1.00]) and 34.7% among individuals 60+ (aPR = 0.65 [0.46, 0.85]). No adverse events were reported."

This is a pretty modest impact, a short duration, and is somewhat clouded by it not being a double blind study.

The rate of infection at 7.62% vs 8.62% are particularly troublesome. As a comparison, it's estimated that 1/3-1/2 of Americans have been infected with Covid.

It's an open question of what the end game would be. Could be that both groups would end at the same infection rate. The masked group might just take longer to get there.

> The masked group might just take longer to get there.

That's not a bad thing. Remember "flatten the curve"?

Avoiding everyone from getting it isn't the goal. Preventing the collapse of the healthcare system is.

We are now into month 17 of two weeks to flatten the curve. Even in the height of the initial wave hospitals were mostly not overwhelmed. Remember the field hospitals and hospital ships that sat empty in New York City?

Yes. We just stopped caring.

https://www.france24.com/en/live-news/20210906-in-covid-swam...

>That's not a bad thing. Remember "flatten the curve"?

That isn't how exponential growth works unfortunately. As long as the exponent is greater than 1 eventually you will get a large peak.

Only if a population is infinite.

How could you possibly construct a double blind study on masks?

Study is worthless. They did not have the means or funds to properly census the body of people involved, they only took blood samples from consenting symptomatic people and they were highly preselective in choosing the regions they included to achieve the outcome they sought.

Cloth masks are quite effective against viruses with a droplet based spread. Widespread mask use came as close to wiping out last year's Flu season as we've ever seen.

>Amid COVID-19 pandemic, flu has disappeared in the US

NEW YORK (AP) — February is usually the peak of flu season, with doctors’ offices and hospitals packed with suffering patients. But not this year.

Nationally, “this is the lowest flu season we’ve had on record,” according to a surveillance system that is about 25 years old, said Lynnette Brammer of the U.S. Centers for Disease Control and Prevention.

https://apnews.com/article/flu-has-disappeared-us-pandemic-2...

However, during the same period where the Flu disappeared, there was a massive Covid surge, because cloth masks are not an effective means of filtering an airborne virus from the air you breathe.

Here's one of the scientists on President Biden's Covid advisory board being interviewed on PBS.

>Studies that have been done show that if an individual might get infected within 15 minutes in a room, by time and concentration of the virus in the room, add a face cloth covering you only get about five more minutes of protection.

On the other hand if you use the n95 respirators and fit them tight to your face, you can actually spend 25 hours in that same room and still be protected.

https://www.pbs.org/wnet/amanpour-and-company/video/do-masks...

To get the kind of protection people imagine that cloth masks provide, you have to wear the same sort of masks that medical professionals are required to wear while treating patients who have an airborne virus.

Which is not surprising since we know Covid is fully airborne.

Unfortunately, those of us on the left have rejected this news in the same way that the crowd at a Trump rally rejected Trump when he told them that they should get vaccinated.

Cloth masks are not an adequate substitute for vaccination, especially for children too young to be vaccinated who are now expected to attend full school days.

Flu was almost eliminated in Sweden as well and we had almost no mask usage. Feels like social distancing was the more important factor.

The issue is that the early measures we took with Covid were based on the false assumption that Covid has a droplet based spread.

Now that we know it is airborne, we have to change our focus.

An n95 mask can help filter the air you breathe and a cloth mask cannot.

In indoor public spaces, we don't need the security theater of disinfecting surfaces. That money would better be spent on improving ventilation.

Isn't the flu generally transmitted through touch? i.e. hand to mouth. I was under the impression the reduced flu rates were due to hand washing, hand sanitizer, and potentially from masks preventing people from touching their face. But not the filtration masks provide.

The entire point of the masks was to catch the large droplets that people cough or sneeze out when they are infected with a virus that has a droplet based spread.

That prevents those droplets from landing on surfaces where others will come in contact with them.

> Widespread mask use came as close to wiping out last year's Flu season as we've ever seen.

I don’t think masks get alll the credit here, not even most possibly. The US was busy spraying down shopping carts with alcohol, fogging stores with disinfectant, and wiping every surface we could find with Lysol. Turns out that does nothing for Covid, but it’s extremely effective against flu virus.

> Widespread mask use came as close to wiping out last year's Flu season as we've ever seen.

This is an assertion. It could have been the fact that nobody was traveling last year. It could have been the fact that most kids were out of school. It could have been distancing. It could have been any number of other things.

Any conclusion here is premature.

The conclusion that cloth masks are ineffective against viruses with an airborne spread, while a properly worn n95 mask does provide real protection is hardly premature.

Here's the quote above from one of the scientists on President Biden's Covid advisory board in context:

>Needless to say, masking is political hot button beyond anything I've ever seen in public health.

At the same time i think we've all done a disservice to the public.

When you actually look at face cloth coverings, they actually only have very limited impact in reducing the amount of virus that you inhale in or exhale out.

Studies that have been done show that if an individual might get infected within 15 minutes in a room, by time and concentration of the virus in the room, add a face cloth covering you only get about five more minutes of protection.

I've been really disappointed with my colleagues in public health for not being more clear about what can masking can do or not do.

On the other hand if you use the n95 respirators and fit them tight to your face, you can actually spend 25 hours in that same room and still be protected.

The bottom line though is by telling people that in fact just putting a face cloth covering on is going to protect you is simply not true.

https://www.pbs.org/wnet/amanpour-and-company/video/do-masks...

People are flailing away to claim that cloth masks "do so do something" in a very counterproductive way. I'm reminded of Ivermectin proponents.

> The conclusion that cloth masks are ineffective against viruses with an airborne spread, while a properly worn n95 mask does provide real protection is hardly premature.

You're just asserting it to be true, so yes, it is.

> I've been really disappointed with my colleagues in public health for not being more clear about what can masking can do or not do.

I agree with this, but probably not for the reason you're saying it. It's hard to "be clear about what masking can do", when you haven't actually bothered to gather any evidence for it, one way or the other.

> You're just asserting it to be true, so yes, it is.

I'm not the one who asserted it. One of the scientists on President Biden's Covid advisory board did.

Unfortunately, many of us on the left are no more willing to accept this truth than those on the right are willing to listen when President Trump tells them they should get vaccinated.

The science on mask mandates for young school children is unclear. Most European countries don't require it.

https://nymag.com/intelligencer/2021/08/the-science-of-maski...

As far as schools are concerned, Delta is a completely different virus. Outbreaks appear to be much more common in the US this fall with Delta, compared to this spring before Delta became the dominant strain. It's difficult to make long term comparisons and draw definitive conclusions when the mutations are great between semesters.

The Delta variant is more contagious so there is a higher rate of infections, but it's not a completely different virus. Symptoms in children are no more severe than with earlier variants.

"Among all hospitalized children and adolescents with COVID-19, the proportions with indicators of severe disease (such as intensive care unit [ICU] admission) after the Delta variant became predominant (June 20–July 31, 2021) were similar to those earlier in the pandemic (March 1, 2020–June 19, 2021)."

https://www.cdc.gov/mmwr/volumes/70/wr/mm7036e2.htm

I don't disagree, that is why I added a qualifier immediately before my statement about Delta.

At least for the children too young to be vaccinated, the Delta variant might as well be a completely different virus.

Previous versions of Covid were unlikely to infect children below puberty at all.

>More kids were hospitalized with Covid-19 this month than any other time this past year -- proving how seriously the Delta variant can hit any age group.

Between August 20 and 26, an average of 330 children were admitted to hospitals every day with Covid-19, according to the US Centers for Disease Control and Prevention.

"This virus that we're dealing with now is a game changer," said Dr. Mark Kline, physician-in-chief of Children's Hospital New Orleans.

"It's just so easily transmitted from person-to-person." As of August 9, he said, "half of the children that we've admitted have been under the age of 2."

https://www.cnn.com/2021/08/31/health/covid-delta-variant-ch...

The Netherlands had fully opened elementary schools since February, UK since March, without any masking and related drama and with barely any distancing. Child Covid-19 mortality has remained very low throughout, even with Delta (grand total of 7 deaths in the UK in the last 6 month).

All the drama around masking at schools seems largely an American phenomenon, where it looks like it's just another flag to signal if you're in Team Red or Team Blue.

So am I understanding the study correctly?

> Those living in villages randomly assigned to a series of interventions promoting the use of surgical masks were about 11% less likely than those living in control villages to develop COVID-19

The surgical masks are 11% more effective in preventing COVID infection than not wearing masks at all?

No, you are not interpreting it correctly. The 11% reduction is the effect of the intervention (encouraging people to use masks), which meant that the rate of people complying with the measure went from 12% (control) to 42% (intervention). The 11% refers to the effect of increasing mask use by that magnitude.

So, having roughly one third of the population wear the mask reduced symptomatic infection of roughly a dozen percent. Can one suppose that an almost fully compliant population would see a reduction of symptomatic infections of roughly one third - or am I missing something?

Can this study suggest that a compliant population should see roughly one third less infections?

Edit: for example, the study lasted, I understand, only a couple of months: so, will this timeframe be enough to suppose that the exponential effects can be taken into account, and that the reduction in the infections should be more than just tripled, if one supposed almost full compliance?

Not quite. The wording has to be parsed carefully:

> Those living in villages randomly assigned to a series of interventions promoting the use of surgical masks were about 11% less likely than those living in control villages to develop COVID-19

So it's not mask vs. maskless; it's promotion of masks vs. no such promotion.

The study [0] gives more information:

> In villages that received the intervention, mask use increased by 29 percentage points (from 13 percent in the comparison villages to 42 percent in treatment villages).

[0]: https://www.poverty-action.org/study/impact-mask-distributio...

I missed the use of word "promotion". It would be interesting to see the difference in just use of the masks.

> It would be interesting to see the difference in just use of the masks.

Indeed it would, but I think getting a large-scale trial with a sufficiently high compliance rate would be a challenge, to say the least.

That's overall community effectiveness, and with only 50% mask compliance:

“It’s notable that even though fewer than 50% of the people in the intervention villages wore masks in public places, we still saw a significant risk reduction in symptomatic COVID-19 in these communities, particularly in elderly, more vulnerable people.”

And the protective effect was even more pronounced in the elderly:

The protective effect increased to nearly 35% for people over 60 years old.

Quite convinced we have to prepare on getting infected some time. Covid will be around for the coming years and years. Nice that you have less chance of getting that, and then what? You can’t walk around with a mask indefinitely. Saw another report this week that links to the viral load and the impact: low viral load = no symptoms, no immunity. Medium viral load is minimal symptoms, Immunization. High viral load = serious illness (and immunity, but potentially also hospitalisation and/or long covid) Would be nice if the masks help you to get in the sweet spot.

> You can’t walk around with a mask indefinitely.

I want to be clear I'm not advocating for this, but you can't? Why not? What's the time limit?

Why not lockdown forever, and everyone social distance and isolate? We CAN do that right?

> Why not lockdown forever, and everyone social distance and isolate? We CAN do that right?

Can we? I mean a lock down has economic consequences that I just don't see from mask use. Maybe technically it's possible, but one of these things is not like the other.

I'm not advocating for permanent mask use. I'm not even advocating particularly hard for mask use in general right now (I mean we probably should). I'm not advocating for mandates. But I keep seeing mask use being presented as some great hardship, that can only be born briefly (if at all) and I just don't see it.

I'm not really arguing in favor of it... the point was we shouldn't just do something permanently because it reduces risk and it's possible. It's absolutely possible to adapt everyone into long term lockdowns, and I believe parts of Australia are in this right now, but we can clearly see that it is a bad idea.

> But I keep seeing mask use being presented as some great hardship, that can only be born briefly (if at all) and I just don't see it.

In my opinion, it's not being done consistently in a way that makes sense. It's at best a lazy rule to make everyone behave the same way. Not everyone is spreading the virus, so it follows not everyone should wear one, yet there are zero attempts at factoring this in to mandates. It's everyone regardless of health.

Again, at best it's a lazy implementation that enables authorities to do blanket power grabs instead of creative solutions that work not just for the vulnerable but also the majority of people who are already protected in some way.

Reduce but not by much. One could buy KN95 masks at comparable costs and wear them longer and be safer. Not sure why people would get a surgical mask. Governments must subsidize quality masks!

What people seem to be missing is that this study only covered a limited period. While surgical masks can slightly reduce the risk of contagion for individual interactions, over a longer period all of us will eventually be exposed regardless of what precautions we take. The virus isn't going away.

Think of it like a soccer goalie defending against an endless series of penalty kicks. He might block the first few balls but eventually one will get through.

https://www.businessinsider.com/delta-variant-made-herd-immu...

This is why it's so important for people who haven't yet been infected to get vaccinated. And take other steps to strengthen your immune system such as reducing obesity, maintaining adequate vitamin D levels, and engaging in the recommended level of physical activity.

https://www.cnbc.com/2021/03/08/covid-cdc-study-finds-roughl...

https://vitamin-d-covid.shotwell.ca/

https://bjsm.bmj.com/content/early/2021/07/21/bjsports-2021-...

Things I wish everyone knew and acted on:

1. Masks reduce spread (this study)

2. Covid-19 is an airborne disease and primarily spread through aerosols

3. Being in a poorly ventilated space (even if everyone is masked) with an infected person means a significant chance of being infected.

4. While (1) is true for even meh-masks, to prevent infection in (3), you need to be wearing a tight-fitting high quality mask. No beards, no cloth, no surgical. N-95 or better with total seal.

This is truly great news, as we've need some controlled studies.

However, _mandates_, literally threatening people with police violence, bodily or financial harm, is not the correct way forward.

I think the best solution is improved mandates for airflow. It's a lot easier to improve airflow in a building than it is to police and enforce a mask mandate.

>However, _mandates_, literally threatening people with police violence, bodily or financial harm, is not the correct way forward.

Maybe I'm missing something, but is this actually a thing? Who in the mainstream proposing police violence, bodily or financial harm? The worst I've heard (in the U.S.) is that a business may not allow you to enter if you're not wearing a mask, which is well within their right and reasonable.

> Who in the mainstream proposing police violence, bodily or financial harm?

People with some flavor of libertarian viewpoint have often explained how every piece of legislation is ultimately backed up by physical force from police officers. Ultimately, if you violate any government policy: whether it is taxation, opening up an illegal lemonade stand, or trying to attend a restaurant that has a vaccine mandate imposed on it, it is ultimately physical force that backs this up if compliance is refused.

As far as financial harm: see the government strongly encouraging corporations to mandate vaccines or other similar policies.

Libertarians like to make this argument about any government enforcement action.

If the government tells you that you can't play loud music after 10pm and you do it anyway, eventually someone will issue you a citation. If you refuse to pay that, eventually you'll get a court summons. If you fail to appear, eventually a police officer may arrest you. If you resist, they will use force to make you comply.

It's a bit hyperbolic, but it is a standard libertarian/objectivist "gotcha".

It's a pretty solid gotcha.

It's a terrible gotcha. It's only effective on people who already agree with you.

Imagine a town council meeting where someone is proposing a $25 fine for crapping on the sidewalk. And a libertarian pops and screaming "You're saying you want to use violence up to and including murder to keep our sidewalks clean!"

Again technically there is a hypothetical chain of causality from sidewalk crapping fine to bodily harm/murder, but no one other than another hardcore libertarian is going to be convinced by that argument.

Absolute nonsense. It’s merely walking through the chain of events and realizing that all dictates are backed by force.

The fact that people “don’t agree” means they’re morons. It is fact.

Well it's not saying "nothing should be enforced ever because all enforcement is backed by violence", it is just acknowledging the reality of it and then determining if a particular rule justifies that, and then farther down, if a rule enforced by violence is unjust, determining whether the enforcing party is an enemy or not.

Generally libertarians only allow for rules against behaviors that violate the rights of others because of this, and I think that's about right.

> You're saying you want to use violence up to and including murder to keep our sidewalks clean!

Because that's what you _are_ saying. Laws are enforced by the police, and they are able to be enforced by the police because the police are legally able to use force. I do not understand what other view there is to take on the issue. In my mind, it's not an opinion, it's a fact.

It isn't a gotcha, it is just thinking through the second, third, etc order of what you are proposing.

Which it is totally worth it when the counterfactual would be a dumbass playing loud music every night. Is there another solution to this that doesn't require ultimately the use of force?

There are plenty of options in between "person breaks law" and "person is the subject of lawful violence". They include things like warnings, fines, and the like. However, all _those_ things are backed by the possibility of the end result being violence. All of them follow a path of either the person doing what they're supposed to... or violence. The only variables are the number of steps until you get to violence... or the person doing what they're supposed to... or the rest of the society deciding to change the definition of "supposed to do".

https://www.bbc.com/news/world-europe-53934952

> A minimum €50 (£45) fine will be slapped on anyone breaking rules on face coverings - in shops, public transport or elsewhere

This is officially government policy in the PRC, as well as many other places.

Other countries will absolutely subject you to police intervention for failure to wear a mask.

At the end of the day all government mandates come with an implied threat of violence, but that aside, since we are talking about Bangladesh in this thread, I know some people from there and the police regularly beat people in the street for violating covid mandates and they even broadcast the beatings on television as a deterrent.

In my country you are removed and fined if you are seen indoors or outdoors where you can't keep a distance without a mask.

It's when I read comments like yours that I feel so jealous of the US. You don't even know what living where I am is like. For you it's like a place that couldn't possibly exist. :P

> It's when I read comments like yours that I feel so jealous of the US.

And then the same Americans ban you from Reddit if you complain about the lockdowns or forced mask mandates.

1. The people that are in charge of making such decisions (scientists, politicians, etc) said you should (and in some cases must) wear a mask. They said that doing so is more for the protections of others, but it also helps the wearer.

2. The impact of wearing a mask, with the exception of a small subset of people, is negligible. At most, it's very slightly uncomfortable.

Given those two things, choosing _not_ to wear a mask makes you a bad person in the eyes of most people; and rightfully so. You are unwilling to put forth a minimal effort to help protect those around you.

And yes, if everyone sees you as a bad person because of your chosen actions, then you can expect to shun/comdemn/avoid you. That's how society works across the world.

Now that this study has come out, with actual numbers, hopefully the recommendations will change; or at least it will spur some research to try to confirm the lack of protection provided by cloth masks. Recommendations were made based on existing information. New information is added and recommendations/actions are taken based on that. That's how science is _supposed_ to work.

I don't want to get in to a philosophical argument, but here in Sweden pretty much no-one wears masks anywhere.

Have you not heard of the lockdowns here in Europe?

In Spain we were forced inside for 2 months, and then forced to wear masks at all times in public - indoors and outdoors.

The police got a free pass to beat and arrest people with the excuse of masks or curfew: https://elpais.com/espana/2021-03-28/la-policia-investiga-a-...

I got banned from some subreddits just for posting that, because it's become such a political issue in the US.

And don't forget that all of this was ruled illegal a year later. All fines reimbursed, but who gives us back the time that was stolen from us?

I don't think there's a country wearing masks in Europe as much as Spain did (visited many times during the last 1.5 yrs) but it doesn't translate well with infection numbers compared to other EU countries that had lax or non existant rules regarding masks.

>Who in the mainstream proposing police violence, bodily or financial harm?

This is what you do whenever you propose a fine. Ultimately fines are paid because otherwise men with guns will threaten you if you don't hand over the money.

We spruce it up with layers and layers, but at the end of it if it comes down to it, it is enforced by men with guns.

This is the popular sentiment on most Canadian subreddits:

https://www.reddit.com/r/vancouver/comments/pgr2sl/it_is_pas...

Anecdotally, I was personally assaulted for not wearing a mask because I took it off after needing to use my ventolin to prevent an asthma attack in a mall. I only need to remove it for about 2-3 minutes at a time the odd time I feel an attack coming on, which only really happens when the weather is really aggrivating me during the hottest summer months where I am. That was enough time for some lunatic to come suckerpunch me in the back of the head and run away.

I've seen people yelling and screaming at others, store employees putting their hands on elderly people not wearing masks and pushing them around. Mobs of masked people surrounding and intimidating individuals who were not masked in places they were not required to be.

There were reports of police breaking into homes and physically removing people that were visiting over Christmas.

I could go on and on...

Someone sent it to me a little while ago.

Enjoy. https://youtu.be/5ByEppIvsDc

It's gone beyond proposal to actually happening in some places. There are some scary examples coming out of Australia.

https://youtu.be/XOKPtYdDh20?t=232

https://twitter.com/Lukewearechange/status/14330657788032655...

Why not? It's harm reduction. You're required to wear a seat belt and have car insurance. Cigarette manufacturers are required to put warning labels on their products. Wearing a mask is annoying and unfashionable but not that annoying. Plus, when COVID numbers drop, mask mandates are again lifted.

This is naive. There is a significant portion of the population that are not going to cooperated with health safety protocols unless there is a real chance of them going to jail or getting a fine.

We're talking wearing a mask and saving lives.

Based on my experience living in a "red state" in the USA, it really doesn't take that level of sanction. People almost universally wore masks in grocery stores here when: a) it was a state mandate/law and b) the asshole state politicians kept their mouths shut about it. Prior to the state mandate there was a patchwork of business and local health dept mandates that were far less well observed. Then subsequently (when the governor changed from Dem to GOP) the politicians realized they could score points with the "not gona do it" crowd by criticizing mask wearing and we went back to nobody wearing masks. And finally, delta variant seems to have scared a significant cohort into voluntary mask wearing.

> We're talking wearing a mask and saving lives

This study doesn’t show that - it shows a slower rate of transmission, but without vaccination, the long term infection rate will ultimately be the same.

Let's conduct a thought-experiment.

Would most people be cooperating with the health and safety protocols if there was an outbreak of Ebola?

> We're talking wearing a mask and saving lives.

What if they don't want your input in their lives?

I don't get this mindset at all. Temporarily masking up at pretty much zero impact to the user vs. upgrading all building's HVAC system.

But upgrading HVAC systems is far more effective.

Sure but is it realistic, especially in the short term?

It's been nearly two years and COVID is likely not going away.

Temporarily? In what was is any of this temporary if COVID is going to be endemic?

At some point we need a way forward, and that really shouldn’t require masks in all public settings.

BTW - masks completely destroy my beard, so they’re not ‘zero impact’ by any means. ;-)

I have a beard myself, how could I have forgotten about that.

You're right, long term, improving ventilation is how to reduce exposure, in the meantime though, I don't think it's too much to ask to mask up.

It's been 2 years. How many more do I need to wait?

I was militant pro-mask when I was unvaccinated. Now that I'm vaccinated and have no comorbidities, I'm OK with being exposed to COVID-19. In fact, I want to have a mild case of COVID-19 to get natural immunity. Natural immunity seems to be more effective than the vaccine for long lasting immunity.

Do you have a good source on this?

https://www.science.org/content/article/having-sars-cov-2-on...

I’m not quite at that point of “fuck it, I’m vaccinated, come at me”, but I have to travel soon and the country I’m transiting through (Iceland) now requires a test.

I’m nervous about it because I’m vaccinated, so I very well could have a mild infection and not know it, and get denied boarding and quarantined at home.

At least it’s an antigen test and those miss most non-symptomatic infection anyway.

Or you could test yourself daily at home before your departure day and remove the element of surprise.

But a positive test isn't forever. I could test positive today (and disqualify myself for 2 weeks) while I could test negative next week.

Plan was to lay low for the couple weeks before departure.

Self-tests are hard to come by here.

Because of disparity between states and the large number of anti-vaxxers, We probably will never reach herd immunity which means that Covid-19 will become endemic and everyone will eventually catch it. With the mutations and winding down immunity it is likely to stay with us.

So, getting a vaccine significantly reduces the risks of death and and getting exposed to the virus naturally will be our immune booster.

That’s why I’m quite relaxed now, I expect to get infected at some point. Maybe not today but in few months when the vaccine induced antibodies can no longer prevent the infection.

Even if there were fewer anti-vaxxers, the Delta variant is so contagious that we won't be able to reach a level of herd immunity sufficient to protect unvaccinated people. All of us can expect to be exposed eventually.

https://www.businessinsider.com/delta-variant-made-herd-immu...

IIRC the CDC says there is evidence that vaccinated individuals can spread the delta variant. So it's important for everyone to continue to wear masks, even those vaccinated. It helps keep those who can't get vaccinated safe, and it helps reduce load on the hospitals so people can get timely treatment for other concerns. Additionally, breakthrough cases are a breeding ground for further evolution of the virus.

My first reaction was to consider this as pretty damning of mass use. But when I considered it more I don't think the study is as damning of masks as it is of mask mandates.

The problem is only ~30% more people wore masks in the intervention arm of the study. So the best possible outcome, removing 30% from the infection group entirely (essentially taking them out of the population -- a "perfect spherical mask" approximation), is a 30% reduction in cases. Which is substantial, but no one expects masks to be that effective anyway. 11% seems a reasonable ballpark.

If everyone had worn masks it would have been easier to measure the effect of just the masks.

Still, it's worth considering the big picture. If mask mandates aren't enforced, they're not worth a whole lot. Especially if you have limited political capital to spend.

The interventions the article mentioned did not include a mandate.

Yea true, more like encouraging people to wear masks.

The problem with this mask business is it treats masks as the only variable. The United States is incredibly unhealthy and most people do not get enough exercise or spend enough time outdoors. It would not surprise me if governments would obtain better results by telling citizens to exercise regularly and eat healthy. Instead it seems like governments are doubling down on a strategy on scaring/bullying out of shape citizens into staying at home afraid.

The most rediculous policy of all is governments requiring masks for outdoor exercise.

11% is frankly not going to move the needle. I could probably reduce my chance of dying in a vehicle accident by way over 11% by refusing to ride bicycles. It simply isn’t meaningful.

Maintaining the recommended level of physical activity cuts COVID-19 death risk by 4× compared to being sedentary.

https://bjsm.bmj.com/content/early/2021/07/21/bjsports-2021-...

And before anyone claims that it's just a correlation, please read the whole paper. The authors did a good job of establishing causality.

> cuts COVID-19 death risk by 4×

And halved severe illness.

No, the study is about a ~11% decrease of infections after a ~30% increase of mask use after an awareness campaign.

> masks for outdoor exercise

I really hope that is for the jogging in the market area of Delhi (I hope this was at least in urban areas).

It wasn't the mask wearing it was the distancing when I was in the military mission oriented personal protection taught us never to issue surgical masks when they're touched they're contaminated and need to be thrown out.

ITT: either this place is turned into Reddit with a bunch of retards bots or none of you can read statistics or can even do basic math.

Is to possible to measure or control for behavioral, vs direct transmission blocking, effects of masks? If they seem more effective for old people, could it be that they help remind people about the ongoing pandemic and infection risk, and signal that mask wearers prefer to keep distance to others.

without controlling for average time spent at various distances it seems hard to get any conclusion from this.

if wearing a mask results in people staying away from you, is the mask effective, or is distance effective?

Why didn't they test N95 masks?

>Why didn't they test N95 masks?

The difference between a cloth mask and an n95 mask when dealing with an airborne virus has been tested.

On the other hand if you use the n95 respirators and fit them tight to your face, you can actually spend 25 hours in that same room and still be protected.

https://www.pbs.org/wnet/amanpour-and-company/video/do-masks...

alternate hypothesis is statistically insignificant. with a 300k sample size a p-value 0.04. damn.

TLDR;

ARR/month estimate:

Lower bound: 2.86E-05

Mid-range: 8.91E-05

Upper-Bound: 1.50E-04

That's on page 90.

How about when the surgical masks get reused?

If a study found the opposite, would we be hearing about it?

Does the paper reveal the seroprevalence by control village and intervention village? I just scanned it and can find no such information.

EDIT: Table A14 is the closest I can find but it is only coefficients, not the underlying counts.

This study didn't perform seroprevalence sampling.

It did: "Blood samples were collected from N=10,952 consenting, symptomatic individuals."

From https://www.poverty-action.org/sites/default/files/publicati... , pg 2, Abstract section, para 2

No that wasn't sampling in the sense that you asked the original question. They only tested symptomatic individuals. They didn't test representative random samples of the intervention and control groups.

From Martin Kulldorff, esteemed (though contrarian) Harvard Med epidemiologist:

"Odd that mask advocates are excited by this study. As a vaccine advocate, I would be horrified if a vaccine trial showed 11% efficacy. Based on the 95% confidence intervals, we do not even know if surgical mask efficacy is more than 0%."

https://twitter.com/MartinKulldorff/status/14332026511062016...

I think this thread is a decent refutation that the CI lower bound was at 0:

"First, the 11% reduction comes from a 30% increase in mask-use. The IV estimate (naively scaling things linearly) would thus be more like a 37% reduction in COVID from going from zero to universal masking."

"Second, we find much larger effects among the elderly (a 35% reduction among 60+ without the above scaling). This suggests that the total reduction in morbidity and mortality from universal masking may be considerably larger than even the 37% number, perhaps more than 50%."

"Third, it's not quite an apples to apples comparison because we are estimating the community impact of masks, whereas the vaccine studies only isolate the individual protective effect. The efficacy of vaccines at the population level may be larger than trials imply."

https://twitter.com/Jabaluck/status/1433129444940599296

EDIT: Woops, read wrong. Lemme post the quote instead.

So an increase of 13% masking to 42% masking led to an 11% effective drop in COVID19 spread. So even though 70% of people weren't affected (either the 13% who wore a mask anyway, or the 60% of people who ignored the mask advice), you still had a measurable decrease in COVID19 spread.

Which means masking mandates / masking propaganda works. Even with the huge number of people who ignore it, its still an effective means to cut down on COVID19 spread.

Except that was not what was tested. Here is what they did:

>No-cost free masks distribution - One-third of the intervention villages received a cloth mask and two-thirds of the intervention villages received a surgical mask[5] during household distribution and distribution at marketplaces and other public locations weekly or every fortnight. Masks were also distributed at mosques on three Fridays during the first four weeks of the intervention.

>Offering information on mask-wearing - Along with the distribution, the research team showed a brief video of notable public figures discussing why, how, and when to wear a mask. The video featured the Honorable Prime Minister of Bangladesh Sheikh Hasina, the head of the national Imam Training Academy, and the national cricket star Shakib Al Hasan. During the distribution visit, households also received a brochure based on WHO materials depicting proper mask wearing.

>Reinforcement in-person and in public - In an effort to create a social norm, mask promoters encouraged non-mask wearers to wear a mask, providing a mask if the individual did not have one. Mask promoters also played public service announcements in public areas using handheld microphones.

>Modeling and endorsement by trusted leaders. - Religious leaders (imams) discussed the importance of mask-wearing at Friday prayers from a scripted speech provided by the research team.

This is a test of the effectiveness of these public policies and not the effectiveness of masks in general.

Hmm, are you suggesting that those public policies might have had an impact on covid transmission that wasn't mediated through mask-wearing? For example, having the imams discuss the importance of mask-wearing might discourage people from going to Friday prayers? That seems unlikely but conceivable.

Not really. What's being suggested is that what's being tested is both societal compliance combined with mask effectiveness. To dramatically over simplify, let's assume we have a population of 10, none of them mask wearers. Let's also assume masks are 100% effective at preventing Covid infection. These measures convince only 1 person to wear a mask.

In the control group (no advocacy) 10/10 are infected. In the study group 9/10 are because that one person wore a mask. So we've got an effectiveness of 10%, despite masks in our contrived example being 100% effective. The effectiveness is blunted by lack of compliance.

>Hmm, are you suggesting that those public policies might have had an impact on covid transmission that wasn't mediated through mask-wearing?

That wasn't the intention of my comment, but yes that is also true. As the article notes:

>"In the intervention villages, they also saw a slight increase in physical distancing in public spaces, such as marketplaces."

My original comment was more directed at the fact that these public policies are not 100% effective in getting people to wear masks. Therefore the society reduction of 11% is not comparable to the vaccine efficacy numbers which are measured at an individual level. If we measured vaccine efficacy numbers using this societal approach, the numbers in the US would be abysmal considering our active case numbers are quickly approaching the peak of the pre-vaccine waves.

They did all of those things, but this paper is about the effect of mask-wearing (surgical vs. cloth vs. none) on the rate of symptomatic seroprevalence in the groups. Kuldorff is right, and is just stating the top-line numbers from the paper.

>Free mask distribution and promotion reduced the proportion of people who reported COVID-like symptoms on average by 11 percent, which was driven mainly by the effects of surgical masks. Villages where cloth masks were distributed experienced a 5 percent reduction in symptoms, while villages where surgical masks were distributed saw a reduction of 12 percent. About a third (40 percent) of those who reported COVID-19 symptoms agreed to have their blood tested for SARS-CoV-2. On average, researchers found a decrease of symptomatic SARS-CoV-2 infections of 9 percent. This reduction was higher in villages that wore a surgical mask (11 percent) and in these, among individuals aged 60+ (35 percent).

It is measuring the effectiveness of the public policy and comparing how it differs when the masks distributed were cloth versus surgical. There is nothing in this report about the effectiveness of masks on an individual level.

"This report" does gloss over much of the results from the actual study. Here's the link to the paper:

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

And at 9%, some of that is likely seeing trusted public figures essentially saying "it's not safe out there" by talking about masks, and people restricting their actions accordingly. It's really hard to actually test this.

> There is nothing in this report about the effectiveness of masks on an individual level.

The DANMASK RCT [1] provided a direct test of masks as personal protective equipment, and found no support for masks. The criticism of that study, at that time, was that it didn't test the hypothesis of protecting others. So here we have an RCT that tests that hypothesis, and now that's not good enough, because the results aren't "at an individual level"?

Boy, the ground sure is slippery around here!

[1] https://www.acpjournals.org/doi/10.7326/M20-6817

And then see this response to that claim by one of the study's authors: https://mobile.twitter.com/Jabaluck/status/14331294449405992...

which seems to have been deleted in the meantime

Better link: https://birdsite.xanny.family/Jabaluck/status/14331294449405...

I wouldn't really call it better if it doesn't have a proper certificate.

because compliance was voluntary... the study merely had leaders in the community wear masks and provided free masks to those that wanted them plus education and reminders; it wasn't a compulsory thing so this is mainly a lower bound on effectiveness.

> Providing free masks, informing people about the importance of covering both the mouth and nose, reminding people in-person when they were unmasked in public, and role-modeling by community leaders tripled regular mask usage compared with control villages that received no interventions, the researchers found.

Is this guy serious? It was not a split between 100% of group A using masks and 0% of group B using it. It was more like 40% / 15%. Is it that easy to become a tenure in Harvard? I think I am applying.

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