Masks Work. Really. We’ll Show You How
nytimes.com
nytimes.com
So, yes, if we have a tight definition of both "masks" and "work" we can say that masks work. But we don't care if a piece of fabric can catch droplets, we care if public use of masks in a pandemic helps slow the spread of that disease.
They do not test how long the masks stop droplet transmission. Other studies say that these masks start losing effectiveness as soon as you put them on, and most masks are ineffective after a few hours.
And, again, we do not care if masks stop droplet emission. (It's very likely that they do). What we care about is whether the public wearing masks in a pandemic stops virus transmission, and at the moment we don't know if it does or not.
“This is a very powerful visual tool to raise awareness that a very simple masks, like these homemade cotton masks, do really well to stop the majority of these respiratory droplets,” Fischer told CNN.
The study itself tests 14 masks.
You're just reinforcing your priors ...
Statistical analysis from the South Carolina Department of Health.
https://scdhec.gov/news-releases/dhecs-third-data-analysis-m...
https://scdhec.gov/news-releases/update-mask-requirement-dat...
Mask proponents say we need to wear a mask to prevent us spreading our covid to other people.
When you touch your mask you transfer covid to your hands. You then need to clean your hands immediately. You may have excellent hand hygiene, but we know (because there are hundreds of studies on this) that most people do not wash their hands often enough, and don't wash their hands properly.
If the science is telling you to wear a mask it's telling you to keep it on and stop touching it.
Some data someone else in the thread posted: https://news.ycombinator.com/item?id=24952278
https://www.cnn.com/2020/03/02/health/surgeon-general-corona...
https://www.cbsnews.com/news/coronavirus-surgeon-general-jer...
Are people on HN actually too stupid to learn how to properly wear a mask in 8 months time? I don't believe that. I think that each of us is smart enough to do that research and train ourselves.
That attitude is precisely what’s wrong with this situation. An elite who’s prescribing technocrat-informed decisions instead of offering balanced and neutral scientific conclusions. Meanwhile you can point to a long line of completely wrong technocratic advice during the pandemic.
Always make sure you’re able to say “I might be completely wrong.”
And sure, I accept that I, and other scientists, make mistakes. To err is human. What about you?
But at any rate, we can see for ourselves how great an impact those mask mandates had:
https://rationalground.com/mask-charts/
https://swprs.org/wp-content/uploads/2020/09/france-masks-ca...
https://thefederalist.com/2020/10/29/these-12-graphs-show-ma...
Mask mandates don't seem to be associated with any impact on the graphs of positive test results, anywhere. If they don't work then they should not be used for all kinds of reasons, dangerousness is by no means the only factor that should determine decisions. Consider also cost, impact on the environment, choking hazards, comfort, psychological distress created by the appearance of fear and so on.
But as some of the writing on this acknowledges, masks long ago became purely political, so we should expect people to keep arguing from different assumptions and not agreeing.
1. https://nscr.nl/naleving-drukte-en-social-distancing-tijdens...
Medical masks protect in two ways. One, they filter the air at an extremely high level. Two, they are fluid resistant, so the saliva droplets that are filled with virus particles cannot penetrate the mask.
Most health organizations, including mine, are noticing that COVID prevalence within their employees is less than the local population as a whole despite being around contagious COVID patients all day long. The major difference in these two populations is that health care workers are wearing medical masks.
Most medical masks are made of the same material out of China that filters > 95% of infectious particles. If you want extra protection, you can look for masks with an "ASTM Level" that gives additional support that the mask is medical grade.
Regarding the rest of the video, his claim of "masks have no effect" seems to be easily demonstrated as false from his experiments. Yes, some smoke does leak, but compare that to him exhaling without a mask. You would get a blast of vape smoke right in your face. The masks clearly filter some smoke and deflect the rest of the smoke away from where he's facing. While obviously not perfect, it looks like a clear improvement to me.
Finally, comparing smoke to covid-19 is disingenuous. You will almost never find individual virus particles floating around the air, they will instead be contained in water droplets which you exhale.
Is this the best we can do?
If it's legitimate KN95, it probably protects at least as good as a medical mask but probably not as good as a N95. This is because KN95s are not designed to form a complete seal so many folks will have some leakage around the edges. This is the reason that you see many systems 3d printing molded frames to improve the KN95 fit and decrease leakage.
By the way, I don't make or sell masks. I'm just interested in keeping people out of the hospital and my friends/family safe.
eg: wear a mask 20 min at a time, then change with another while leaving the previous in open air to dry. Cycle 3 masks like this. Total mask lifetime (until effectivity drops to <75%) with this usage pattern: 10 hours.
The US military was the wrong place to look for a general solution to a civilian crisis.
All advise given from a military context relies on the idea that the civilian administration will step in, and coordinate, or handle things on its own.
For example, the military is advised not to do long term criminal investigations... but that’s not because detective work is valueless, but because it’s expected that the civilian police will handle that.
Many (not all) HN readers, being software engineers, have a high level of pretentiousness that comes from being good in one field, and then carry over that arrogance into areas where they have no clue.
Suddenly, you see software engineers pretending they know more than sociologists who have studied the topic for years and dismissing their evidence out of hand or merely responding to the title of the article, without engaging its substance.
We see it quite clearly whenever any topic from the social sciences is discussed, be it discrimination, social inequality, government regulation, taxes or the welfare state.
It's quite embarrassing indeed.
The irony is to watch people get up in arms when an article is posted by some expert in another field who does the same. Its kinda funny thr amount of HN comments I've seen where some user says something along this lines of "author has no idea what they're talking about and should stick to xyz"
Or maybe they trust scientists who are saying that we don't have good evidence yet?
https://www.thelancet.com/journals/lancet/article/PIIS0140-6...
> Although direct evidence is limited, the optimum use of face masks, in particular N95 or similar respirators in health-care settings and 12–16-layer cotton or surgical masks in the community, could depend on contextual factors; action is needed at all levels to address the paucity of better evidence. Eye protection might provide additional benefits. Globally collaborative and well conducted studies, including randomised trials, of different personal protective strategies are needed regardless of the challenges, but this systematic appraisal of currently best available evidence could be considered to inform interim guidance.
This para says we don't have enough evidence, and what we have isn't particularly good, and we need more evidence, but in the mean time the bits and bobs we have could guide us.
This is why I say "people should wear masks, masks may help, but we need better evidence".
All the way through your article there are people saying that the science is not clear.
> But for the variety of masks in use by the public, the data are messy, disparate and often hastily assembled.
[...]
> So, scientists have relied on observational and laboratory studies. There is also indirect evidence from other infectious diseases. “If you look at any one paper — it’s not a slam dunk. But, taken all together, I’m convinced that they are working,” says Grabowski.
> But such studies do rely on assumptions that mask mandates are being enforced and that people are wearing them correctly. Furthermore, mask use often coincides with other changes, such as limits on gatherings. As restrictions lift, further observational studies might begin to separate the impact of masks from those of other interventions, suggests Grabowski. “It will become easier to see what is doing what,” she says.
https://scdhec.gov/news-releases/dhecs-third-data-analysis-m...
https://scdhec.gov/news-releases/update-mask-requirement-dat...
Highlights:
When comparing the jurisdictions that have mask requirements in place to those that don't, the jurisdictions with mask requirements have shown a 44.2 percent greater decrease in the total number of cases during the five weeks after the requirements were implemented.
Jurisdictions without mask requirements have experienced an overall increase in total cases of 1.2 percent when compared to jurisdictions with a mask requirement in place.
https://www.ncbi.nlm.nih.gov/pubmed/19216002
https://www.cambridge.org/core/journals/epidemiology-and-inf...
https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1750-2659...
https://www.cmaj.ca/content/188/8/567
https://academic.oup.com/cid/article/65/11/1934/4068747
https://www.ncbi.nlm.nih.gov/pubmed/19216002
Is laughably underpowered. 2 people got a cold in one group, 1 in the other. There's nothing to derive from this.
bin-Reza is a review that does not agree with your statement.
Radonovich et al compares N95 and surgical masks, and finds no difference between those.
One has to actually read and critically evaluate scientific papers to learn something.
Offeddu et al is the same.
Long et al is the same.
So none of these links support your claim.
Meta-analysis of randomized controlled trials (RCTs) indicated a protective effect of masks and respirators against clinical respiratory illness (CRI) and influenza-like illness (ILI)
Meta-analysis of observational studies provided evidence of a protective effect of masks and respirators against severe acute respiratory syndrome (SARS)
For some further evidence, see Hong Kong; Nearly 8 million people live in some of the densest city of the world; from day one, hkers have been wearing masks en masse and implementing cleaning precautions -not just hands but also doors and lift buttons, etc;
The result is an infection rate proven to be extremely low: 700/M infected and 14/M deaths. That’s about 1/40th the rate of the US. This without hard confinement.
There have been additional measures to stop the importation of the virus, like enforced quarantine and intermittent closures or early closure of some businesses.
There has also been a mass test of more than 1.5M people with only about 40 cases found, so the infection rate _is_ really low.
What has not happened because of the mask? no deaths, no marked increase in hospital admissions for respiratory illnesses or infections caused by masks, no-one got carbon dioxide poisoning...
Is wearing a mask pleasant? No, it’s a pain in the a and I was quite sceptic at the beginning. I still think we may be overdoing it a bit in HK since there is so little infection, but no-one here is ready to live another SARS, so people do what’s right and don’t complain.
We have lots of RCTs on mask wearing (mostly in healthcare professionals) and they struggle to find a benefit.
People should wear masks, masks may help, but it's unhelpful when people misrepresent the strength of the evidence.
I say, do it anyways, I'll wait patiently for the science at literally any point in the future. If it turns out masks, statistically, do nothing, then I will be no worse off for trying.
But when we're trying to persuade as many people to wear masks as possible it's really unhelpful for people to make dishonest or misleading claims about the effectiveness of masks.
A message of "we think masks work, and here's why" is more persuasive than "masks definitely work and you're an idiot if you think otherwise" because it's very easy to find good quality studies that don't show a benefit to mask wearing.
We're all supposed to wash our hands after going to the bathroom, especially if we're preparing meals for others -- California makes this very clear with their mandatory signage!
But do I need to see the science behind it? I've never seen any hard data on hand-washing -- and yet...
> but it's unhelpful when people misrepresent the strength of the evidence
What exactly are your credentials, and why should I trust you?
This is false. If you look around and read actual studies, not demand other people to do it for you and not cherry pick garbage studies, you'll find even real life "experiments" of healthcare workers in the US during COVID-19 not wearing masks with rapidly rising number of COVID-19 cases then mandated to wear masks with subsequent rapid drop of cases.
What you won't find though is studies supporting the assertion that sick person wearing a mask protects others, not the wearer. Those are the studies that show little to no benefit and always did actually. You protect others with a mask by not catching the virus yourself, it's a second order effect.
> not demand other people to do it for you and not cherry pick garbage studies,
The reason I ask you to provide the studies you think are persuasive is so we avoid the tedious discussion about cherry picking. I cannot cherry pick articles that you supply.
If you want my link: https://www.thelancet.com/journals/lancet/article/PIIS0140-6...
Lancet is a reputable high impact publication. The paper is peer reviewed.
> Transmission of viruses was lower with physical distancing of 1 m or more, compared with a distance of less than 1 m (n=10 736, pooled adjusted odds ratio [aOR] 0·18, 95% CI 0·09 to 0·38; risk difference [RD] −10·2%, 95% CI −11·5 to −7·5; moderate certainty); protection was increased as distance was lengthened (change in relative risk [RR] 2·02 per m; pinteraction=0·041; moderate certainty). Face mask use could result in a large reduction in risk of infection (n=2647; aOR 0·15, 95% CI 0·07 to 0·34, RD −14·3%, −15·9 to −10·7; low certainty), with stronger associations with N95 or similar respirators compared with disposable surgical masks or similar (eg, reusable 12–16-layer cotton masks; pinteraction=0·090; posterior probability >95%, low certainty).
For masking they find only "low certainty" evidence, and that's with N95s or 12 to 16 layers of cotton. (Most people are wearing 3 to 4 layers).
Low certainty comes from GRADE and means "The true effect might be markedly different from the estimated effect" -- masks may be markedly more, or markedly less, effective than they found.
> What you won't find though is studies supporting the assertion that sick person wearing a mask protects others, not the wearer. Those are the studies that show little to no benefit and always did actually. You protect others with a mask by not catching the virus yourself, it's a second order effect.
Oh-ho, so here we see a clearly shifted goalpost. Everyone else in this thread is saying that the science is obvious and that you wear a mask to prevent your infection from spreading to other people. So, does the science support "source control" or not?
The Lancet article looks at dozens of studies of the relationship between mask-wearing and infection with coronaviruses. (Some SARS, some MERS, some COVID-19.) Those studies fall, without exception, into the three following categories.
1. A few saw no cases of infection with or without masks, and therefore tell us nothing about whether masks help and how much.
2. One saw no cases of infection with masks and just two without masks (in a fairly small sample). It somehow manages to report a relative risk of 1.03 for wearing masks (!), which I can only assume is the result of some statistical adjustment that doesn't quite make sense in this case. (The real conclusion from this one is: "This study doesn't provide enough data to draw any conclusions.")
3. In every single one of the others, wearing a mask was associated with lower probability of infection. Some of the studies weren't powerful enough for the difference to be (on its own) statistically significant, but all of them pointed in the same direction and the underpowered ones had relative risk point-estimates similar to those of the not-underpowered ones.
Sure, they report this as "low certainty" because, e.g., none of these studies was a proper randomized controlled trial. Sure, we would do well to get more data. But I see no possible way to characterize what it says in the ways you have.
They don't "struggle to find a benefit". They readily find a very considerable benefit. They don't "not show benefits". They absolutely do show benefits. There are issues: we don't have e.g. nice big RCTs where someone has somehow contrived to have two otherwise identical large populations of the general public make different mask-wearing choices, and that means that there is inevitably some uncertainty in applying the results to the question of what benefit there is from getting the public to wear masks. But it 's pure grade-A bullshit to say that the studies "don't show benefits".
If a single globule of liquid leaving an infected person's mouth, whether due to a cough, a sneeze, or just a spitty staccato spoken statement, is a transmission opportunity. If a mask catches only one such drop, then it has lowered the risk of transmission.
Hell, having all conversations with a pair of underwear on your head (covering your mouth and nose) would help.
People saying otherwise are either truly ignorant or intentionally lying.
Now maybe masks ultimately provide such a modest benefit relative to their cost and discomfort as to not be worth it, but we just don't know and probably never will definitively know.
It does not. It's possible for a filter to break some droplets into smaller droplets that linger in the air for longer. Evidence suggests that masks are still a net benefit, but this is by scientific study, not "by definition".
Would you mind sharing your source?
Thanks!
This link talks about neck gaiters
https://scdhec.gov/news-releases/update-mask-requirement-dat...
They're using I think single layer of cotton, and 2ply or 3ply disposable paper masks. These are very low quality masks, and if masks work people probably shouldn't be wearing these.
Loosing effectiveness over time is very, very different than being actively harmful as is claimed upthread.
Since we cannot test all possibilities here, it is then left to intuition and "wisdom". I have to believe that significantly reducing the number of virus particles in the air while allowing a few to linger longer would be preferable to the opposite.
As I have observed, people are terrible at judging distances. I am probably more likely to get infected by a spray of cough droplets at close range than a few individual tiny droplets floating in the breeze. If I had my way, most people would be wearing masks permananently (and also not allowed to come within 3 meters of me), virus or not.
[1] SARS-CoV-2 viral load predicts COVID-19 mortality
Elisabet Pujadas, Fayzan Chaudhry, Russell McBride, Felix Richter, Shan Zhao, Ania Wajnberg
https://www.thelancet.com/journals/lanres/article/PIIS2213-2...
On an individual level yes. On a population level, probably. But studies are few (and difficult, relying on natural experiments).
The important question isn’t whether a mask reduces transmission but how much people change behavior. For example: you really need to go somewhere and the bus looks full. Does people wearing masks on the bus increase the likelihood that you get on it? You don’t want that to happen
There is a line somewhere. People saying otherwise are either truly ignorant or intentionally lying.
Japan does not do better compared to other Asian countries like South Korea or Taiwan, because the other Asian countries enact more measurements than Japan other than just masks. Japan pretty much doesn't really care that much about Covid compared to other Asian countries but they always wear masks.
My wife is going to office everyday (Tokyo), she is also going to a wedding party tonight, and also next week. Life is really going pretty much normal right there.
A visual demonstration why masks don't work: https://videopress.com/v/4egEyh2b
We did not identify any experimental volunteer studies that investigated whether surgical masks or N95 respirators could protect against infection: https://www.cambridge.org/core/journals/epidemiology-and-inf...
Face mask use in health care workers has not been demonstrated to provide benefit in terms of cold symptoms or getting colds: https://pubmed.ncbi.nlm.nih.gov/19216002/
The volume that goes through directly, does so with reduced velocity. Meanwhile what goes around - doesn't go "everywhere". Instead it stays localized.
Now we remember the fact that masks don't cancel social distancing but instead go hand in hand - and it seems to show that it would in fact provide a benefit - containing the aerosol in a smaller radius around the mask-wearing individual.
https://www.nature.com/articles/d41586-020-02801-8
This article has some good links to studies and articles, some math and science.
It also points out you don't even have to science very much, there is lots of anecdotal evidence that shows that in gatherings where masks are worn, transmission is slowed.
Lot's of other factors play into that, but you only have to math a wee tiny bit to realize that properly worn masks can help fewer people be infected, and therefore fewer people will die.
MATH.
This has some nice visualizations based on anecdotal evidence and statistical analysis and compares transmission rates in different settings given the variables of masks wearing vs. no masks and ventilation vs no ventilation, while also taking into account surface based transmission.
https://english.elpais.com/society/2020-10-28/a-room-a-bar-a...
Fauci: “The seasonal flu that we deal with every year has a mortality of 0.1%.”
Mortality for Covid is 0,14%: https://www.dw.com/en/coronavirus-who-estimates-10-of-global...
That is probably not healthy, is it? Or not?
If I shot 100 golf balls at you directly most of them would hit you.
If put a soccer net between us but closer to me the thrower of golf balls some number of those golf balls would not hit you anymore... so you would be hit by less than 100 golf balls.
And even better if there is a soccer net close to me and a second soccer net close to you even less of the 100 golf balls would hit you.
Probably not completely accurate but close enough.
Mask that cover your face tight + filters = success
Masks that we now have = fail
Nice animations should not supplant actual evidence.