Has there ever been a study that shows whether face masks work when used in public with COVID? I keep looking, and I find it kind of incredible that we're two years into a pandemic, and except for one study in Bangladesh with masks (that wasn't really that clear) - there is nothing to say that any of these masks are working.
There are a bunch of studies with the Influenza virus (different virus) and surgical masks in school settings, both with and without disciplined hand washing - and the meta-analysis of those studies suggests that masks (not N95) - don't really do much to prevent transmission of the virus.
I religiously wear my 3M 8210 N95, tight enough to leave welts on my face and indentation in my skull - so clearly I would like to believe it's helping - but I would kill to see a good Randomized Control Trial. Obviously wouldn't be double blinded - because of course you would know you were wearing a mask - unless you gave one cohort faulty masks, and the other ones actual filtering masks.... The ethics of doing this with Covid are obviously questionable, unless you could find a group that had already made the decision not to wear masks...
Randomized Control Trials are not the one and only way to prove something.
> Conclusions: Parachute use did not reduce death or major traumatic injury when jumping from aircraft in the first randomized evaluation of this intervention. However, the trial was only able to enroll participants on small stationary aircraft on the ground, suggesting cautious extrapolation to high altitude jumps.
If N95 masks in a virus laden environment are akin to parachutes when falling from an airplane - that's great news. I'm super happy to be educated on this given my unbroken record of never having been indoor in 18+ months without one. Happy to know that it's been making an absolute difference.
> Upgrading face masks to filtering face piece (FFP3) respirators for healthcare workers on covid-19 wards produced a dramatic reduction in hospital acquired SARS-CoV-2 infections, according to research carried out at Addenbrooke’s Hospital in Cambridge.
> Once FFP3 respirators were introduced [as opposed to simple surgical masks], the number of cases attributed to exposure on covid-19 wards dropped dramatically—in fact, our model suggests that FFP3 respirators may have cut ward based infection to zero.
FFP3 is a bit better than N95 (it's equivalent to N99).
N95 masks came from industry, but there were no RCT studies there. People just noted that they obviously worked, through arguably one can easily feel that a saw dust mask works as opposed to one against viruses.
I've done extensive research on this subject, for coronavirus purposes N95 is equivalent to FFP3. The most important aspect is having head bands (as opposed to ear loops) to secure a tight fit. N95 typically have head bands. FFP2/KN95 (filtering equivalent to N95) typically don't, which is why FFP3 are sometimes preferred. There are also regulatory reasons to use FFP3.
3M also manufactures FFP3 masks. Not sure if they sell them outside EU though.
Sure, they're not the only way - but they are definitively the best way, and nothing is stopping this kind of study from happening, especially in low risk (age) groups / populations.
I think it might even be ethical if you could find such a low-risk cohort that was adamantly opposed to the wearing of masks, and under no circumstances whatsoever, except perhaps because they are scientific minded individuals and would like to prove they are not required, would wear them.
Given other beliefs those people are likely to hold, at least here in the US, I suspect there would be some other behaviors they would be systematically more likely to engage in that would act as confounds.
That "one study in Bengladesh with masks" involved 342,183 participants and produced clear evidence that masks work. What is the point of more studies if folks are just going to dismiss them out of hand?
Lazy dismissal of scientific work is something of its own epidemic on HN these days. "Ah, but this study doesn't address this laundry list of things I just made up, and I haven't bothered to look at other sources, and I probably haven't bothered to even read this study, actually." It's especially common on COVID-related studies amongst the anti-maskers and anti-vaxxers on the site, but I have been seeing the same kind of lazy dismissal on lots of other posts as well. It's effectively an evolution of the Gish gallop.
I find it both dreary and frustrating, personally, and it's not terribly surprising that people like the poster above call people out on it.
But - I was super excited by the Bangladesh study, and spent the better part of a half hour or so trying to see if I could tease out some clear evidence that masks work. I'm insanely pro-mask, and was way ahead of the curve back in february 2020, when a lot of the mainstream was suggesting masks don't work (If that's the case, then why were we trying to reserve them for first responders in hospitals?) - and encouraged everyone I know to wear them. I've spent hours reading the Japanese Meta-Analyses of mask usage in influenza scenarios, looking for differences in Coronavirus and Influenza Virus behavior.
I have never, not once in 18+ months gone indoors where other people are, without wearing an N95 Mask (after I was able to source them ~ June 2020).
I don't think it's an exaggeration that a lot of the last two years of my life have been dedicated to both encouraging (strongly) everyone I know to wear a high-quality, well-tested N95 from a well-known trusted source, as well as scouring the internet for solid research on the effectiveness of masks.
I'm not lazily dismissing that Bangladesh study - I just came away from it not being particularly encouraged that it provided evidence that the masks / methodology presented there would shut down a pandemic by preventing transmission. I'm eagerly and enthusiastically looking for evidence to confirm my bias that masks work.
I like to believe that HN has at least been partially successful in holding itself to a higher standard than the internet at large, through a combination of community guidelines, overall community belief in the guidelines, and thoughtful moderation.
You could, of course, say the same thing about personal attacks: They're endemic on the internet and to humanity, but we've mainly kept them out of HN using the above measures.
Lazy dismissal is often the top comment on any given post, COVID or not. It's harmful to discussion and I would argue antithetical to the hacker spirit: If we only allow perfect airtight products/proofs, we miss out on discovery and exploration. Perhaps some guideline to avoid lazy dismissals (or something along those lines) would go a long way.
I keep looking, and I find it kind of incredible that we're two years into a pandemic, and except for one study in Bangladesh with masks (that wasn't really that clear) - there is nothing to say that any of these masks are working.
Was what was seen as a lazy dismissal. I should have spent more time expanding on why I didn't think it was really clear, but the point I was really trying to get at - is that there has been a lack of experimentation, trials, research - despite the millions of lives lost and many billions of dollars spent (Trillions?) - and I was really hoping someone would respond with a pointer to such a RCT that we could all read.
Unfortunately the takeaway wasn't that we should spending more time to demonstrate that masks work, but that I was dismissing that they did. The absolute opposite of what I was attempting to do. The failure in communication is clearly mine, and I'll try and be a little more expansive in the future.
For the record, what I really should have written was,
"To date, there have been no studies that have reassured me that I could go indoors into a crowd of infected, unmasked people, confident that as long as I kept my well-fit 3M 8210 N95 mask on, that I ran < 0.1% chance of being infected by Covid. The Bangladesh Study that showed 8.6% of people in the control villages reporting Covid symptoms and 7.6% in the experimental villages, did not provide me that kind of reassurance, thought I think it provided statistically significant results that masks as a general public health NPI are effective at reducing transmission of the Coronaviruses under study at the time."
Of course - Omicron essentially reset all expectations for transmissibility.
It "produced clear evidence that masks work"...if you think a 10% reduction in the speed of transmission is "working". That's a pretty minimal return for a large intervention (30% increase in mask-wearing).
Plus, they had to throw out 26 villages with 0 infections in order to get that much of an effect. Now there is a certain logic to that, but I wager that if most of those 26 villages had been ones with the intervention, they would not have thrown them out; I'm not aware of that part of the analysis being pre-registered.
They probably don't have a non-zero impact, but it appears to be pretty small, even with a massive intervention like the one in Bangladesh.
The Bangladesh study failed to produce a significant result when simpler nonparametric statistics were used to analyze the data. There were also significant discrepancies in the follow up rate between the control and treatment groups. And even if you ignore those issues, the absolute effect size (20 cases) was tiny. The effect size was expressed in terms of the relative rate of symptomatic seropositives, i.e., normalized by population denominators, which makes it appear larger and is sensitive to the follow up rate discrepancies (see above).
Don't get me wrong - the Bangladesh study suggested that masks were a good public health initiative and should be used. What it didn't do was reassure me that they were a strong individual NPI.
In much the same way that not masking was recommended early in the pandemic as a public health initiative to reserve the masks for first responders - wasn't particularly good advice for the individual.
So - several threads here. It’s not unreasonable to try to understand what helps globally as well as individually. Early on, when supply chains for masks were stretched or non-existent, we were instructed not to wear masks. This was good advice globally, as it reserved the limited supply for those who could most benefit from them (first responders) - but bad advice individually. If you were looking for guidance to protect yourself and those you loved, following global advice was not the best path.
Likewise, the current guidance that wearing masks - particularly if they are well fit FFP3/99%+ filtering, is good advice globally, but it’s unclear if it’s sufficient to reduce the risk down to <.1% for the individual (the point at which I would pretty much not worry about social distancing and avoiding stores, workplace, etc… I’m <65 and vaccinated, So I would be comfortable with a 1/1000 risk of catching Covid, particularly as I can usually avoid those scenarios)
The question isn’t whether masks are an important NPI - they absolutely are - particularly if we could convince people to avoid going indoors unmasked and ensuring they are wearing (and not taking off) well fit FFP3s, the question is whether that is sufficient to mostly eliminate the risk of catching Covid.
One lesson I learned here is that you really need to expand on your thoughts and not assume everyone else is already on the same wavelength as yourself.
That's not what I have been reading about the study. The evidence seems to be on the pro-mask side, but it does not appear to be _that_ clear. I'm not an expert in masks, health, or even statistics, so I'm not here to say you are right or wrong. I'm just pointing out that there is a debate. That itself is enough to want to look for more studies, don't you think?
To answer your question, the point of more studies is to increase confidence in our opinions and decisions, make better findings, realize errors, etc. And you are quickly jumping to conclusions with "folks like you are just going to dismiss them out of hand".
Now, my question would be: what do you mean by "folks like you"?
Have you looked at the study itself? From the abstract: “Mask distribution and promotion was a scalable and effective method to reduce symptomatic SARS-CoV-2 infections.”
The existence of “debate” doesn’t mean anything. Anti-maskers are always going to dispute studies like this, no matter how clear the evidence
Have you looked at the study itself? It found that cloth masks do nothing and surgical masks help a tiny bit. (control: 8.60%; treatment: = 7.63%) I suppose you could parse this as "masks work", I parse this as "if you are really worried about airborne virus, wear N95."
Page 12: "no statistically significant effect for cloth masks"
"We find clear evidence that the intervention reduced symptoms: we estimate a reduction of 11.6% (aPR = 0.88 [0.83,0.93]; control: 8.60%; treatment: = 7.63%). Additionally, when we look separately by cloth and surgical masks, we find that the intervention led to a reduction in COVID-like symptoms under either mask type (p = 0.000 for surgical, p = 0.066 for cloth), but the effect size in surgical mask villages was 30-80% larger depending on the specification. In Table S9, we run the same specifications using the smaller sample used in our symptomatic seroprevalence regression (i.e. those who consented to give blood). In this sample we continue to find an effect overall and an effect for surgical masks, but see no statistically significant effect for cloth masks."
Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that."
I'm still baffled that every mask I see at stores says "not for medical use". It's been nearly two years and we still don't have approved masks?
I'm also seeing more and more evidence that masks that aren't N95s don't do any good. The CDC still doesn't recommend using N95s but recommends cloth masks. They're still claiming that they need to be saved for healthcare workers. REMINDER: WE'RE NEARLY TWO YEARS INTO THIS THING. Our government is pathetic.
To be sure, 'not for medical use' probably means that the manufacturer of the mask didn't want to pay (in money and/or effort) to go through the regulatory process to obtain an official rating; this has more to do with what the market wants (cheap masks! who cares about ratings!) than the government.
There are a bunch of studies with the Influenza virus (different virus) and surgical masks in school settings, both with and without disciplined hand washing - and the meta-analysis of those studies suggests that masks (not N95) - don't really do much to prevent transmission of the virus.
I religiously wear my 3M 8210 N95, tight enough to leave welts on my face and indentation in my skull - so clearly I would like to believe it's helping - but I would kill to see a good Randomized Control Trial. Obviously wouldn't be double blinded - because of course you would know you were wearing a mask - unless you gave one cohort faulty masks, and the other ones actual filtering masks.... The ethics of doing this with Covid are obviously questionable, unless you could find a group that had already made the decision not to wear masks...