[srinivgp]

It's pretty conclusive. It's been conclusive for years and years, before COVID-19. There's no question at all that masks reduce infectiousness through the extremely obvious method of preventing some virus particles from going from one person to another, and also no question at all that probability of infection depends on number of virus particles around, and that viruses in general produce worse symptoms when the initial viral load is higher (and masks reduce the initial viral load via the extraordinarily obvious physical mechanism).

You will find literally zero papers credibly claiming otherwise.

You will find many papers claiming that masks do not reduce the risk to zero. That's obvious and also irrelevant in light of the above.

You will find papers claiming that random cloth masks do not negligibly reduce the risk when you're immersed in a high-virus-density environment for hours on end. Not as obvious, but also irrelevant in light of the above.

If you think you know of a paper that contradicts the above, send it our way please.

[timr]

> You will find literally zero papers credibly claiming otherwise.

Of the papers cited in the WHO meta-analysis of face masks and infection [1], all of the (three!) papers from a non-health-care setting had a confidence interval overlapping 1.0 (i.e. "no benefit"). Of those in a health-care setting, about half had confidence intervals overlapping 1.0 (i.e. "no benefit"):

https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

The literature in this area was exceptionally ambiguous prior to 2020, and hasn't improved over the course of the pandemic. You've just made a provably incorrect claim. If you did it on YouTube, I guess you'd be banned!

(just kidding; we all know that you can't possibly misinform people when you're agreeing with the party line!)

[1] https://www.thelancet.com/journals/lancet/article/PIIS0140-6...

[srinivgp]

The paper you linked to says, in its summary section, "For the general public, evidence shows that physical distancing of more than 1 m is highly effective and that face masks are associated with protection, even in non-health-care settings, with either disposable surgical masks or reusable 12–16-layer cotton ones, although much of this evidence was on mask use within households and among contacts of cases."

But I assume you mean that the meta analysis didn't claim masks were useless, those three underlying papers did? I'm not sure what those three were, though, maybe I missed it. I found all the papers used but there were like a dozen in the non-health-care setting.

[timr]

That is their interpretation of the meta-analysis, yes ("summary section" == "discussion section"). That is not a statement of fact, but of the authors' opinions about the facts reported. The data stands on its own -- though in this case, since it's a meta-analysis with fancypants statistical re-weighting of the data, the line between "data" and "analysis" is decidedly blurred.

> But I assume you mean that the meta analysis didn't claim masks were useless, those three underlying papers did? I'm not sure what those three were, though, maybe I missed it. I found all the papers used but there were like a dozen in the non-health-care setting.

The data they have presented, aggregating ~all of the prior research literature on masks, shows a weak effect, at best. Only by mixing data from different settings (mostly hospitals) and different types of masks (from cloth to respirators) and re-weighting the conclusions do they arrive at this claim of even weak effectiveness.

Do masks work? Based on the literature, the only honest answer is "maybe they have a small effect, but the evidence isn't very good."

Compare this to what you see repeated in the media and by "experts". The truth is...most of these people haven't read the papers, and are just repeating what they've heard.

[kgarten]

Not improved?? I just checked nature...

https://www.nature.com/articles/s41591-020-0843-2 https://www.nature.com/articles/d41586-020-02801-8 https://www.nature.com/articles/s41467-021-24115-7

Seems pretty clear to me.

[timr]

The Leung et. al. paper (first link) should never have passed editorial review. Look at figure 1: the only significant result in the entire paper (1a, panel 3) is based on four data points. I don't know if this is p-hacking, per se, but it's not a robust result. And not that I give the paper a lot of credence, but it's worth nothing that the overall trend across all pathogens is that masks are ineffective against aerosols.

Link two is a news article and contributes no data.

Link three is a survey of people self-reporting a bunch of different things, where they've thrown out 32% of the data for non-response, selected the ones who did respond (bias!) and used that to make claims about face masks. Moreover, their data shows that as people wear face-masks more often, their chance of getting Covid goes up! This paper has so many confounders and potential sources of bias that it simply cannot be taken seriously.

When I said that the research literature on masks over 2020 hasn't gotten any better, these kinds of papers are exactly what I meant. They're terrible, they're littered with methodological and data analysis flaws, and provide no useful information to the debate. If these "seem clear to you", you don't understand what you're reading and lack the ability to assess research literature.

Sadly, top-tier journals publish a lot of garbage, particularly when that garbage is topical and will get press. You cannot use "Nature paper" as a badge of quality. You still have to read and understand the paper.

[kgarten]

For me that these papers get accepted is rather a sign that scientific consensus is on the side of masks work.

Usually, it takes 2 -5 years to get a nature paper ready (at least for the labs I know). Seeing also the pre-prints that were in the article that you dismissed as "news article." and others it seems a strong indication that most virologists and epidemiologists think masks work.

They might be wrong, yet I haven't heard any convincing theory or model on why that should be the case.

[timr]

> For me that these papers get accepted is rather a sign that scientific consensus is on the side of masks work.

Well that's a great way to confirm your biases. The "scientific consensus" was that the earth was the center of the universe, that infection was transmitted by miasma, that plate tectonics were a crackpot theory...I could go on.

Science is the history of well-controlled experiment overturning consensus thinking.

In any case, editorial review is a human process, and like all human processes, has ample sources of error. In this case, a big source of error is that the major scientific journals have spent the better part of 2020 falling all over themselves to publish garbage about Covid that gets press hits.

> Usually, it takes 2 -5 years to get a nature paper ready (at least for the labs I know).

This obviously isn't true in this case. The pandemic hasn't been around for that long!

Also, no, it doesn't take 2-5 years to put together an editorial. Even in normal times.

[kgarten]

> The "scientific consensus" was that the earth was the center of the universe.

Yes, and then somebody found a better model (that's also still wrong) yet explained more and we used it. So my question, what's your better model you base your assumptions on? Any scientific paper is wrong, you can find problems with any of them. Just, critique is easy and often doesn't lead anywhere.

my point: The scientific consensus right now is wearing masks help. This is supported by physics (particle simulations), medicine (respiratory disease and their transmission .. and a lot of other fields.

You say there's little data ... come on than make this > well-controlled experiment overturning consensus thinking

you can be famous!

https://www.japantimes.co.jp/news/2020/10/22/national/scienc...

Check the video, people are trying what would be an experimental setup you would accept? That is also ethically OK.

We have both controlled experiments that have reduced validity in the real world because of the artificial conditions and we have some more messy real world evidence. Seems OK to me.

The people I see on the other side don't offer an alternative model. Also a lot of the criticism comes from people who don't seem to have virology /immunology etc background.

> Usually, it takes 2 -5 years to get a nature paper ready (at least for the labs I know).

Yes, my point was these papers are rushed. It can be bias, it can be also that reviewers have their expertise that tells them the paper fits the evidence.

Change happens over models/explanations. I don't see any new ones from the "Masks don't work" folks. Just criticism (that's easy ... I'm happy to point out all the flaws in any paper you present me. If you want to kill a paper in peer review it's super easy ...)

For policy decisions shouldn't you use the current scientific consesus,however flawed it is? Is there a better solution? Otherwise you are just relying on your gut feeling. Good luck.

[kgarten]

in terms of physics I see a good reason to wear a mask. If COVID did not invent a sneaky way to go around that

Article 2 has a whole lot of pre-prints with data in the citations ... :) Here's a follow up (also with a lot of paper citations : https://www.nature.com/articles/d41586-021-01394-0

Talking with friends who are virologists, they all seem to agree masks help.

What's wrong with the articles the nature commentary are based on And articles like that: https://journals.plos.org/plosone/article?id=10.1371/journal...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7883189/#__ffn_...

[timr]

> Article 2 has a whole lot of pre-prints with data in the citations

This is yet another news article, written by a journalist (Lynne Peeples, who wrote the other Nature news article you've shared upthread) who is mostly re-hashing her previous article. Did you read it or follow the citations? This is an excellent example of hearsay: if you don't take the time to read the citations in detail, you won't realize what you're missing.

Most of the citations here are same citations in the previous Nature news article. Only citations 4-8 deal with the question of masks' impact on transmission (the remainder are for other questions, like whether vaccinated people can be infected). Of the papers in citations 4-8, two are new. Both are based on mathematical models using self-reported survey data and/or state-level case data. I don't know how good these papers are, but all studies of this form are low-quality medical evidence.

Unfortunately, bad journalists can re-hash the same crappy studies faster than skilled people can debunk their work.

> Talking with friends who are virologists, they all seem to agree masks help.

That's meaningless. You can find a sample of scientists to support pretty much anything.

> What's wrong with... https://journals.plos.org/plosone/article?id=10.1371/journal...

So many things. The paper uses survey responses (= bad data), and tries to correlate it with state-level infection curves (= blurry data), and only does it for a month-by-month difference for every month between April and September 2020, when cases were falling across all of north america. It sets arbitrary thresholds for "high cases" and "high mask wearing". It doesn't control for confounding factors, like other policies the states in question might have enacted.

This is a terrible paper. I cannot believe PLOS One published this. It is embarrassing.

> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7883189/#__ffn_...

This is not a paper, it's a review. It presents no data. It summarizes the authors' opinions on other papers.

[kgarten]

So I don't know what you are arguing: We have a lot of evidence on the effectiveness of masks in relationship to preventing droplet infection.

We don't have so much about COVID 19. On the community level it looks promising for me, the papers are flawed but coming out.

What I am missing ... where is the other side of the coin. All models are wrong but some are useful. The particle simulations are wrong, but pretty useful (and I don't see why COVID should behave differently). What model do you base your assumption that masks don't work? Is there research that supports your claims? All science is bad science :) Some is useful.

> survey responses (= bad data)? So any research based on survey responses is bad? It's a standard method in policy research. What data would you use to show the community effect of mask wearing?

I'm usually listening critically to experts in a field (not to dentists or surgeons), it seems people who claim masks don't work are not virologists and have not worked with the virus (COVID19): https://en.wikipedia.org/wiki/Christian_Drosten https://en.wikipedia.org/wiki/Sandra_Ciesek

Both strong in the pro mask camp. Are there virologists working on COVID 19 (in the lab) that are on your side of the argument?

[kgarten]

Anecdotal, how do you explain the non existing flue season (last autumn ) and the low incidences in Japan? We got higher rates during the Olympic.

I live in Tokyo, Japan and visit US/Europe often. The only significant difference I see is the willingness to wear masks. And there's way less space here (packed subways etc.)

[timr]

Well, any rational conversation about Japan has to start with the observation that cases are at an all-time high right now:

https://www.asahi.com/topics/word/%E3%82%B3%E3%83%AD%E3%83%8...

I don't think changing rates of masking can explain that change.

> Anecdotal, how do you explain the non existing flue season (last autumn ) and the low incidences in Japan? We got higher rates during the Olympic.

I haven't seen any data on flu during the olympics, so I can't comment on that. Covid cases, of course, were shooting up long before the first athletes even arrived in Japan (see above).

To answer your question, nobody knows why flu "disappeared" during the last year. My hypothesis is a combination of two things:

1) it didn't disappear, it just spread less due to to the dramatic reduction in international travel (plus maybe closure of schools).

2) we stopped testing for flu at rates necessary to detect it. Our prior surveillance system for influenza was pretty limited, and most of it switched to Covid in 2020.

In general, I think people fixate on masks far too much, because they're visible. Even in Japan, what qualifies as a mask would make Americans in the "mask compliant" cities laugh out loud. I routinely see people wearing these on Instagram and on television:

https://www.superdelivery.com/product_image/812/8/8128738_10...

[kgarten]

... the increase in incidences are coinciding with early travel and reducing the state of emergency related to the olympic. I work at a place that housed one of the teams, and the incidence increased around 1-2 weeks after some people arrived.

NHK made a lot of efforts like the one bellow: https://www3.nhk.or.jp/nhkworld/en/news/backstories/1247/

Check the video,I would say masks help. It's basic physics ...

it's similar to the seat belt and car discussion. It's debatable how much they help (and they might have increased the number of accidents initially), yet they help. Statistics is hard.

[timr]

> Check the video,I would say masks help. It's basic physics

Masks leak. Airflow seeks the path of least resistance. Also basic physics. People are not mannequins in a fume hood with scrap of cloth glued to their slobberhole.

I don't think anyone is disputing the idea that if you could somehow hermetically seal off everyone's face holes, you'd stop the spread of a respiratory virus. But we can't, and we don't, so the question becomes: in the real world (i.e. not a mannequin in a lab), does it make a difference?

All of the real-world evidence on the question is mixed, at best.

[kgarten]

what is the risk of wearing a mask? that you look silly?

the real world evidence is mixed, yes.

People are not mannequins, people die. If a simple action of mine, that might make me look silly, might save some lives (might, I don't know, yet from annexdotes countries that had no problem with wearing masks and other measures faired better) I will do what these countries did (and also wear a mask). It's rational compassion for me.

You might say, I don't care (and science might prove you right or wrong after a long while), yet consider the potential cost if you are proven wrong ... Looking silly versus potentially killing people ... The evidence is not in, and it depends on what you value more ;)

It's your own choice. For me I decided to wear a mask in public, do social distancing and get vaccinated. I think these are reasonable things to ask from people. You don't seem to think that.

[kgarten]

anything that interfere with droplet dispersion is better than nothing ... no? https://www.youtube.com/watch?v=pwOwMsCc6NA

https://www.youtube.com/watch?v=GAvO_QdO9eM

Seems basic to me ... If the droplets from me don't reach to the first person in the cinema I cannot infect them.

[belorn]

> If the droplets from me don't reach to the first person in the cinema I cannot infect them.

It would be nice if that was true. In a small study here in Sweden they tested for covid particles in the AC system, and found particles in every single place they tested. This in a major hospital where everyone are wearing masks, and where the AC is located in the ceiling. The finding was not what the researcher was expecting, especially not in the AC system located on the roof.

How much interference a mask has is determined by the leak rating, but for most surgical masks there are no protection for the finer droplets in coughs and sneezes.

In a similar style, people though initially that bath houses and saunas would be safe against covid because the large droplets in the humid air would drop quickly to the ground. Later it was generally agreed here that the conclusion was incorrect and all public bath houses and saunas closed. Like with masks, humid air might be better than nothing but you really do not want to be near a person who are sick unless you got yourself an air filter and face shield.

[kgarten]

Yes, that's the point masks are better than nothing. They might reduce the likelihood (without much of a negative impact). That's why we should wear them.

A vaccination also just reduces the likelihood you get covid. People can still get it and still spread it, even if they are vaccinated. It just reduces the likelihood and masks might do that as well ...

[timr]

Science is the history of people debunking ideas that "seem basic" to other people.

Those are called "hypotheses", and they're great. The next step is to find evidence that proves the hypothesis...and that's where we're stuck here.

[kgarten]

Science is the history of people seeing something basic and getting told by others that it's not true ... E.g. the earth is round. Yet, You can never prove a hypothesis just present more and more evidence.

My point: it does not hurt me to wear a mask and it might help people, so I will do it. It seems also that scientists who know more about this than me, support this idea. They might be wrong, yet even if they are the negative consequences are so low (I wore a mask for a couple of days ... ) that for me it's worth it.

When I hear Rand Paul, I hear the smuggness of "I know masks don't work" and sorry but we don't know that ... Saying this right now, is showing me that he does not understand science (we don't know, they might help) and that he does not have any compassion.

Fauci seems to have the better track record (seeing how he dealt with AIDS).

[nickthemagicman]

Masks work in healthcare settings due to proper mask usage and training.

The problem is at the community level.

The current world mask usage is: "Wear a filth rag on your face until the waiter brings the breadsticks".

This could actually be doing more harm than good.

[nickthemagicman]

Thanks for posting. No one on the pro-mask side reads scientific papers.

They're fascists and want to crush their opposition through controlling the narrative instead of actual science.

[miles]

> It's been conclusive for years and years, before COVID-19.

March 2020:

U.S. health officials say Americans shouldn’t wear face masks to prevent coronavirus https://www.marketwatch.com/story/the-cdc-says-americans-don...

In fact the U.S. surgeon general recently urged the public to “STOP BUYING MASKS!” “They are NOT effective in preventing general public from catching #Coronavirus, but if healthcare providers can’t get them to care for sick patients, it puts them and our communities at risk!,” wrote Surgeon General Jerome Adams on Twitter.

The CDC said last month it doesn’t recommend people use face masks, making the announcement on the same day that first case of person-to-person transmission of coronavirus was reported in the U.S. The CDC recommendation on masks stands, a spokesman told MarketWatch Wednesday, even with the first reported case of a COVID-19 infection in an individual in California who had not been to China or been exposed to a person diagnosed with the virus.

“The virus is not spreading in the general community,” Dr. Nancy Messonnier, director of the Center for the National Center for Immunization and Respiratory Diseases, said in a Jan. 30 briefing. “We don’t routinely recommend the use of face masks by the public to prevent respiratory illness. And we certainly are not recommending that at this time for this new virus.”

WHO stands by recommendation to not wear masks if you are not sick or not caring for someone who is sick https://www.cnn.com/2020/03/30/world/coronavirus-who-masks-r...

“There is no specific evidence to suggest that the wearing of masks by the mass population has any potential benefit. In fact, there’s some evidence to suggest the opposite in the misuse of wearing a mask properly or fitting it properly,” Dr. Mike Ryan, executive director of the WHO health emergencies program, said at a media briefing in Geneva, Switzerland, on Monday.

[Valectar]

So, you linked a number of articles from early 2020, when there was not significant community spread of COVID and thus the primary strategy for dealing with it was isolating and quarantining individual cases, and most people in the country would probably not come in to contact with someone carrying COVID.

If you want to know what the WHO recommends, you need only look at their website:

https://www.who.int/emergencies/diseases/novel-coronavirus-2...

"Make wearing a mask a normal part of being around other people. The appropriate use, storage and cleaning or disposal of masks are essential to make them as effective as possible."

[Rebelgecko]

The CDC made that statement because masks work. It was worded dumbly, but they're just saying that when the mask supply is constrained, healthcare workers should be prioritized over the general public. If masks didn't work, there'd be no point in triaging who gets them.

[leereeves]

It wasn't hard to find sources that disagree:

> The use of masks, which are medical devices, requires correct use, based on medical principles unfortunately not known by the whole population. This cultural deficiency, linked to the breathing difficulties caused by the use of this filter, has led to incorrect management of these important medical devices, facilitating the commission of errors that can make the masks ineffective or *even dangerous because they can become a vehicle for the spread of the disease itself*.

https://www.sciencedirect.com/science/article/pii/S092575352...

That article cites a WHO statement:

> Using a mask incorrectly however, may actually increase the risk of transmission, rather than reduce it.

https://www.who.int/csr/resources/publications/Adviceusemask...

Edit: what is wrong with people here, downvoting quotes from scientific articles and WHO statements, because they don't like what they say?

[omegaworks]

>Using a mask incorrectly however, may actually increase the risk of transmission, rather than reduce it.

Read your link. Proper usage isn't hard to understand. If you touch your mask with your dirty hands it might increase the chance that you breathe in the germs that were on your hands.

Don't put a dirty mask on your face. Don't touch your mask with dirty hands.

Notice that these messages are different than "masks are a mind-control conspiracy" and "masks are ineffective."

[leereeves]

I see people misusing masks all the time. Read the CDC guidance on masks and check out how many people follow it:

> A mask is NOT a substitute for social distancing.

> Masks should completely cover the nose and mouth and fit snugly against the sides of face without gaps. [People with beards should closely trim their beard or wear two masks]

> Wash your hands with soap and water for at least 20 seconds or use hand sanitizer with at least 60% alcohol after touching or removing your mask.

> Not recommended: Masks that do not fit properly, masks made from fabric that is loosely woven, masks with one layer, masks with exhalation valves or vents.

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

[nickthemagicman]

> You will find literally zero papers credibly claiming otherwise.

Here's a paper that says cloth mask usage increases rate of infection.

https://bmjopen.bmj.com/content/5/4/e006577

Here's a collection of studies refuting mask efficacy.

https://swprs.org/face-masks-evidence/

You're literally a vector for disinformation which is a bannable offense but only the Rand Pauls who go against the narrative get banned.

Your false information you just posted will be celebrated by the echo chamber members of the internet.

[sampo]

> Here's a paper that says cloth mask usage increases rate of infection.

> https://bmjopen.bmj.com/content/5/4/e006577

Using cloth masks only, increased rate of infection in relation to the control group. And the control group: "In the control arm, 170/458 (37%) used medical masks, 38/458 (8%) used cloth masks, and 245/458 (53%) used a combination of both medical and cloth masks during the study period."

So we can conclude that the medical masks, used in the control arm, worked better than cloth masks.

If you were trying to coyly imply that the study said that cloth masks increased infections compared to using no mask at all, you were being dishonest.

[nickthemagicman]

Read that paper again.

Cloth mask wearers had a higher rate of CLI than the control group.

The control group being may or may not be wearing a mask.

"""The control arm was ‘standard practice’, which comprised mask use in a high proportion of participants. As such (without a no-mask control), the finding of a much higher rate of infection in the cloth mask arm could be interpreted as harm caused by cloth masks, efficacy of medical masks, or most likely a combination of both."""

Point is: The CDC mask policy of wearing a dirty cloth rag on your face until the waiter brings the breadsticks is probably not ideal.

[__blockcipher__]

> It's been conclusive for years and years, before COVID-19

What? The overwhelming literature showed the exact opposite! That cloth masks did not prevent Influenza whatsoever.

I'd start with https://aapsonline.org/mask-facts/ as a great review, and then take a look at some specific studies like this one:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4420971/

> The rates of all infection outcomes were highest in the cloth mask arm, with the rate of ILI statistically significantly higher in the cloth mask arm (relative risk (RR)=13.00, 95% CI 1.69 to 100.07) compared with the medical mask arm. Cloth masks also had significantly higher rates of ILI compared with the control arm. An analysis by mask use showed ILI (RR=6.64, 95% CI 1.45 to 28.65) and laboratory-confirmed virus (RR=1.72, 95% CI 1.01 to 2.94) were significantly higher in the cloth masks group compared with the medical masks group. Penetration of cloth masks by particles was almost 97% and medical masks 44%.

> This study is the first RCT of cloth masks, and the results caution against the use of cloth masks.

> The control arm was ‘standard practice’, which comprised mask use in a high proportion of participants. As such (without a no-mask control), the finding of a much higher rate of infection in the cloth mask arm could be interpreted as harm caused by cloth masks, efficacy of medical masks, or most likely a combination of both.

---

The TL;DR is masks were never thought to work for community transmission of any respiratory virus, but they definitely don't work for SARS-2 where the preponderance of evidence points to aerosol transmission as the dominant transmission mode, which masks cannot help against and could theoretically worsen (by increasing the total quantity of aerosols released, and that's before looking at factors like them giving a false sense of security or requiring conversational partners to stand more closely together)

[serf]

>I'd start with https://aapsonline.org/mask-facts/ as a great review, and then take a look at some specific studies like this one:

for one, this was last updated a year ago. That's OK -- but it's jam-packed with 'citations' (many are from non-medical groups like NY Times, so on) from 2020, around 50 of them. Much of the data changed, was redacted, or non-reproducible by other groups.

I read through it until I came upon the second or third 'conclusion' that was at odds with the conclusion of the paper-authors she cites.

The 'curator' of that data is an anesthesiologist who 'teaches constitutional law to non-lawyers', and posts political blogs regarding 'mainstream media propaganda regarding the vaccine and ivermectin' and articles that refer to Kamala Harris as 'another snake slithering out of the swamp'.[0]

Her conclusions may be right, it may be wrong -- but the political axe being ground, combined with the conclusion/data inaccuracies portrayed against the cited works, leads me to believe -- anecdotally -- that the opinions are likely unreliable and biased; it prompts me to want to find other professionals to consult.

[0]: https://marilynsingletonmdjd.com/category/politics/page/5/

[Valectar]

Where did your conclusion of "masks definitely don't work for SARS-2" come from? Just in your quote it stated that the control that cloth mask use was compared to was a population with a high proportion of mask wearing. The study does not compare cloth mask usage to no mask usage, and only says that it is possible that cloth masks are harmful.

Also if you would like some more up to date information, as well as a larger number of studied, which are specific to COVID, the CDC website has a lot of information here:

https://www.cdc.gov/coronavirus/2019-ncov/science/science-br...

[__blockcipher__]

> Just in your quote it stated that the control that cloth mask use was compared to was a population with a high proportion of mask wearing. The study does not compare cloth mask usage to no mask usage, and only says that it is possible that cloth masks are harmful.

That was me debunking the “before COVID, masks were known to work” claim of the GP. That was not a study of SARS-2 but rather Influenza.

The “masks don’t work for sars-2” was in reference to sars-2 aerosol transmission, which masks mechanistically don’t protect against. There is only one RCT of sars-2 in a community setting, and it failed to demonstrate an improvement in the primary endpoint of self-infection. There is no study showing that masks slow the spread of sars-2 in a community. Yet despite the lack of any studies, various medical authorities like the CDC are issuing statements that they do exactly that, which is a classic case of an institution using its credibility to advance baseless claims

[Valectar]

> There is no study showing that masks slow the spread of sars-2 in a community

You say that, and yet "At least ten studies have confirmed the benefit of universal masking in community level analyses"

https://www.cdc.gov/coronavirus/2019-ncov/science/science-br...

And the website goes on to list each of them, as well as a number of other studies relating to the effectiveness of masking.

[__blockcipher__]

Those studies all have fundamental flaws. The basic problem is those are associative studies, which can’t separate the effects of masking from the normal curve of a viral epidemic.

You are right though I should have been much more specific than just “study”.

A question though: if masking is so great, why wouldn’t the health authorities have performed an actual RCT to conclusively prove they work? (We have one RCT for SARS-2 which showed no statistically significant effect on the primary endpoint)

[nickthemagicman]

> It's pretty conclusive. It's been conclusive for years and years

* Citation needed

Pro-maskers think that if they tell people they can fly it's others responsibility to prove that they can't fly.

The burden of proof is on the people claiming that something works.

Do you not understand how science works?

You're saying is 'conclusive' that masks work.

I'm saying you are disengenuouslty parroting media talking points and have to post a scientific paper to prove your claim.

Every paper you will find has flaws and contradiction and inconclusivities.

Texas lifted all Covid restrictions including masks and has lower infection rates per capita than states with mask mandates.

Clearly it's not conclusive.