> that was a misinterpretation of the review in the Covid-skeptic sphere.
No, it wasn't. You should read the paper itself, instead of relying on (sadly) biased editorials about the paper. It literally says what the OP wrote:
> Wearing masks in the community probably makes little or no difference to the outcome of influenza‐like illness (ILI)/COVID‐19 like illness compared to not wearing masks (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.84 to 1.09; 9 trials, 276,917 participants; moderate‐certainty evidence. Wearing masks in the community probably makes little or no difference to the outcome of laboratory‐confirmed influenza/SARS‐CoV‐2 compared to not wearing masks (RR 1.01, 95% CI 0.72 to 1.42; 6 trials, 13,919 participants; moderate‐certainty evidence)
The only place they found any plausible signal was comparing N95 respirators against surgical masks, but the evidence was extremely weak:
> We pooled trials comparing N95/P2 respirators with medical/surgical masks (four in healthcare settings and one in a household setting). We are very uncertain on the effects of N95/P2 respirators compared with medical/surgical masks on the outcome of clinical respiratory illness (RR 0.70, 95% CI 0.45 to 1.10; 3 trials, 7779 participants; very low‐certainty evidence). N95/P2 respirators compared with medical/surgical masks may be effective for ILI (RR 0.82, 95% CI 0.66 to 1.03; 5 trials, 8407 participants; low‐certainty evidence). Evidence is limited by imprecision and heterogeneity for these subjective outcomes. The use of a N95/P2 respirators compared to medical/surgical masks probably makes little or no difference for the objective and more precise outcome of laboratory‐confirmed influenza infection (RR 1.10, 95% CI 0.90 to 1.34; 5 trials, 8407 participants; moderate‐certainty evidence).
The editorial you cited was a low point in the history of Cochrane, where they gave in to public outrage and attempted to cast doubt on their own data.
From the editorial: "It would be accurate to say that the review examined whether interventions to promote mask wearing help to slow the spread of respiratory viruses, and that the results were inconclusive. Given the limitations in the primary evidence, the review is not able to address the question of whether mask-wearing itself reduces people's risk of contracting or spreading respiratory viruses."
Whether you think the editorial was them caving or not, they also issued it under their own name with the same weight as their other reviews, so they must have thought enough of it to do so.
Given that there's ample laboratory evidence of the filtering capacity of a good N95 or even a KN95 mask, and having worked with an N95 respirator in tuberculosis control settings for 17 years and never converted my TB test, I think I'll stick with the mask in future and I have no hesitation recommending winter masking to others who believe they are at risk of complications.
I've liked not being sick for the last three years.
Seriously, what's the difference between what OP wrote:
" [Cochrane] found there was no reliable evidence that masks worked against COVID/"
And the editorial: "the review examined whether interventions to promote mask wearing help to slow the spread of respiratory viruses, and that the results were inconclusive"
How is "inconclusive" functionally different from "there was no reliable evidence?" Seriously, how do you justify this pedantry while ignoring and obfuscating the truth?
People do much evil by focusing on the wrong facts, the wrong stories, and the wrong lessons learned, while ignoring the right ones. That you are willing to focus on apparently frivolous pedantry while ignoring the fact that so many were forced to use masks without any high-quality scientific evidence that they actually did anything, including children, and all the lessons that should derive from this, is in my opinion, very representative of this type of evil.
It's not "inconclusive" and "there was no reliable evidence" that are different, it's the promoting part that makes them completely different.
"We found no reliable evidence that abstinence prevents teen pregnancy"
"We examined whether promoting abstinence prevents teen pregnancy and the results were inconclusive"
The first is obviously wrong, and if the the second is true it would mean the government should look for other ways to prevent teen pregnancy, but it wouldn't mean that practicing abstinence as an individual doesn't work to prevent pregnancy.
> > "We found no reliable evidence that abstinence prevents teen pregnancy"
> > "We examined whether promoting abstinence prevents teen pregnancy and the results were inconclusive"
> The first is obviously wrong,
No. They're equivalent. They both mean "we looked, and we didn't find any confirming evidence." You're confusing "we found no reliable evidence of X" with "we found evidence of NOT X", which is different, and essentially never achievable in empirical studies (note: this is not an invitation to get side-tracked in pedantic debates about proving the null; I'm telling you how actual randomized controlled trials work, in real life.)
Proving a negative via statistics is ~impossible, so what you do instead is to look for significant differences in X, attributable solely or partially to the intervention. If you don't find such a difference (as was the case in the mask review), you say "we found no reliable evidence of X".
But when the Cochrane authors wrote "Wearing masks in the community probably makes little or no difference to the outcome of influenza‐like illness", they really did mean exactly what it sounds like -- the effect size in an aggregated pool of randomized controlled trials was statistically indistinguishable from zero. You can debate whether or not they looked for the right thing (X), you can debate whether or not adding another big randomized trial would help find X, and so on. But the plain-text interpretation is correct.
In medicine you cannot distinguish. It is all about the intervention and not about some theoretical best-case scenario.
The intervention is to ask people to wear masks. People comply as they do in real real life and then we measure the results. There was no reliable evidence that this made any noticeable difference.
Now you can change the intervention – instead of asking and mandating masks as we did, we could educate masks wearers more. Unfortunately we have no evidence that it helps.
Perhaps masking could help to an individual wearer? Alas, we didn't collect such evidence either.
Some studies are lab based. In those masks had some effect. But that's not how people use masks in real life, so these results don't mean much.
> But that's not how people use masks in real life, so they don't mean much.
I think saying "Using X is effective, but only if you actually use X" is obvious. The thing people want to know is "do masks stop the virus" which is an entirely different question from "How many people will wear masks", which is a different question from "What is the effectiveness of interventions to promote mask wearing"
The first question is pointless for someone responsible for public health. People want the answer to it because they don't want to think about all these related issues and have simplistic idea that they can protect themselves. But chances are their compliance is exactly the same as among people in those studies.
Therefore the real question is how effective is the intervention. It will be (or should be) asked by people responsible with public health policies.
P.S. Cochrane group is not for giving scientific answers to individual people. Its main aim is to evaluate the evidence of different treatments and provide guidance to policy makers and healthcare authorities.
If you are responsible for public health and the answer to the first question is "no" then you have no need to ask the other two. Figuring out what we can do to get people to do what works is important too, but it's not the only thing that matters. People can be educated and their habits changed.
We have similar problems getting schizophrenics to take their meds and getting communities with high rates of open defecation to use toilets, but nobody suggests that we give up on antipsychotics or sanitation facilities.
The first answer is too vague to have a meaningful answer in case.
Every other treatment in medicine including schizophrenia is tested how it works in practice. It is incurable disease and the treatments have many side-effects. Thus the question becomes not “does this medicine cure schizophrenia” but “does this treatment works better than placebo or another treatment?”. When studies are completed, we gather evidence by monitoring real life experience with this treatment.
> Every other treatment in medicine including schizophrenia is tested how it works in practice.
Medicine is tested according to how it works when people actually take it. People participating in research studies who fail to take their medications (or their placebo for that matter) are kicked from the program and their data is typically discarded entirely.
In fact, often clinical trials are statistically analysed by intention-to-treat, including all people who have been randomised even if they later don't receive the treatment.
Per-protocol-analysis (including only people who follow the study protocol) can also be used but it is more prone to bias.
Besides, with masks it is not simply wearing or not wearing a mask. Even a very diligent mask wearers may wear it in a way that makes it less effective without being aware of that.
In short, when the doctor prescribes a medicine it is important to understand the factors why the patient may not take the medicine as prescribed. If the real life situation is that most people take medicine in a way that makes it ineffective and so much that the clinical trial cannot find significant effect, then he shouldn't prescribe it. It is just a waste of resources and giving people false hopes.
> In fact, often clinical trials are statistically analysed by intention-to-treat
Fair! That said, intention-to-treat is more likely to greatly underestimate the efficacy of a treatment when non-adherence is expected to be high/isn't being monitored.
> In short, when the doctor prescribes a medicine it is important to understand the factors why the patient may not take the medicine as prescribed.
I agree, but the solution is to help the patient overcome those barriers not to throw out the medication. It's to give people the information and tools they need to follow the treatment. People who wear masks could be trained on how to properly fit them, take them on/off, store them, replace them, etc. The real life situation around masking included basically none of that. "Wear a mask" was basically all people were told.
It doesn't make sense to fault/dismiss masking if a large part of the population isn't wearing them because they were tricked into believing that masks don't work or that masks will actually make them sick, and another large part of the population wears them, but wasn't shown how to do it correctly.
It's important to be aware that those things are going on within the population, but the next step from there is still "educate the public" and not "abandon all efforts at masking" - at least not until a more accessible alternative which is also as effective as masking becomes available
The population was told that masks certainly work, in certain areas mandates made sure that compliance is very high >95%.
If we still could not find reliable evidence that masks are effective, then the policy makers should be told that.
There is very little you can do to improve mask wearing technique. We certainly explained these things to doctors, it made no difference in results. If you want to make more controlled studies, you can do that. Don't hold your breath however.
No, we should not continue requiring wearing masks because you are only doing that out of hope. That's not how we do things in medicine. It would be unethical. There are many medicines that show effectiveness in the lab but fail in clinical trials. We don't demand for those medicines to be used until we find more effective alternative. Many unknown factors could cause ineffectiveness in clinical trials, we don't need to understand all of them, just the fact that the drug failed to demonstrate effectiveness and safety in real life settings.
>> a more accessible alternative which is also as effective as masking becomes available
The point is masking was not effective. It has not shown effectiveness anywhere in the real world.
There is very much plenty of fairly reliable evidence that masks work. And the better the compliance the better they work. In nurse studies you get much better results than in population studies, for instance. Now that I'm looking I'm hard pressed to find any studies that go against this conclusion.
The latter sounds like advertising and education about masks rather than wearing the masks themselves. ie telling people to wear masks made no difference in spread probably because people’s minds were already made up about masking.
I din’t see it making any conclusion about masking itself
I'm completely sure masks hurt my pocketbook and my ability to keep my car tidy, and that forcing people to mask has additional costs. There are cost/benefit questions that aren't as trivial as you imply, and they should be made based on reliable data.
Your existence is valuable to me for, if nothing else, potentially interesting Hacker News discussion. I wish your comment was a better example of that. I am engaging in the hopes you can do better.
Throughout the pandemic, my family and I have been careful about being around others. We have masked with N95 or KN95 masks when we couldn't stay home. I cut my beard for a better fit. We got vaccinated as we were able, and enrolled one of our children in a vaccine trial (he wound up in the control group). We have tested pretty often, and as best we know none of us has contracted the virus. I'm meeting my responsibilities to society around not spreading coronaviruses.
I'm also trying to meet my responsibilities to society around engaging with issues honestly. It's disheartening to see people who probably share my position on an issue behaving poorly.
Pretending that downsides don't exist is more likely to lose you the argument than win it. Spouting abuse and insults means people stop listening. Please do better.
There are studies that show cheaply made surgical masks shed microplatic fibers which end up in the lungs of those who wear them over prolonged periods.
Absolutely false. There are lots of negatives to mask wearing, starting with inducing developmental problems in children and continuing on with massive increases in long lasting trash and then into more speculative issues with breathing. It's not a harmless activity.
> they also issued it under their own name with the same weight as their other reviews, so they must have thought enough of it to do so.
Data is data. Editorials are editorials. The fact that they're published on the same website doesn't change the data. If the Higgs boson was published in the same issue of Physics Letters B as another letter that claimed uncertainty of the result, would you treat them with equal weight?
> and having worked with an N95 respirator in tuberculosis control settings for 17 years and never converted my TB test
I mean...that's fine? Nobody is telling you what to believe or do. Most of what we do comes without evidence. But let's be slightly rigorous thinkers for a moment: there's a fairly obvious difference between a fit-tested n95 mask in a laboratory setting, where there are lots of other interventions happening at the same time (negative pressure labs, hoods, etc.), and putting on a loose surgical mask on a bus. We should be able to talk about that rationally, and not resort to superstition.
> I've liked not being sick for the last three years.
I haven't worn masks and I haven't gotten sick either. Other than Covid -- which I got when we were all wearing masks.
That's drawing an unnecessarily sharp description. To a first approximation all Cochrane pieces are editorials. They're interpreting what's actually out there.
> But let's be slightly rigorous thinkers for a moment: there's a fairly obvious difference between a fit-tested n95 mask in a laboratory setting, where there are lots of other interventions happening at the same time (negative pressure labs, hoods, etc.), and putting on a loose surgical mask on a bus. We should be able to talk about that rationally, and not resort to superstition.
No one's resorting to superstition. You're the one saying there's no value in an intervention that has empiric laboratory evidence to support it. The argument here is what matters at the population level. If the problem is performance, then we train people to select and use masks better, not simply say that there's no point to it at all.
The review found very few studies into the effectiveness of N95/respirators against ILIs, and from those studies they concluded "wearing N95/P2 respirators probably makes little to no difference".
Bear in mind a possible source of confusion here: TB bacterium are ~3 microns in size, but viruses are about 0.2 microns. The Cochrane review I mentioned is only about respiratory viruses. So it's possible that they may work against TB but not against flu or COVID.
I'm pretty aware of how large a TB bacillus is, thanks.
The NIOSH definition for an N95 is a device able to filter at least 95% of airborne particles that have a mass median aerodynamic diameter of 0.3 micrometers. While SARS-CoV-2 is around 0.1 microns in size, naked COVID-19 viruses in air are rare as they would be torn up nearly immediately, so they are almost always within aerosols. Typical respiratory aerosol range is around half a micron or so [0], and as the aerosol particle size gets smaller, so necessarily must be the amount of virus that is present.
Is this perfect filtration? No, but no one gets sick from a single virus they inhaled either, even with as communicable as the current Omicron variants are. There's a minimum infective dose and they help keep exposure under it.
The size of the single virus is a false metric here. There is a wide range of respiratory droplets containing virions. Those droplets can range from visible (way bigger than a mycobacterium ) to only large enough to hold one virion. The size distribution of those particles is the metric.
Yup, we lead lives where it's simply not that big an issue to protect ourselves. While I think my chance of dying from getting it would be very low the issue of long term damage is another matter--it certainly looks to me like it damages everybody, just not always to the point they notice. The damage is probably cumulative.
It also literally says "The high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies hampers drawing firm conclusions."
It does, and that's true, but that doesn't contradict what OP wrote.
They found only mid-to-low quality evidence supporting the use of masks to prevent ILI. That evidence, for everything but the question of "n95 vs. other", showed an effect size statistically indistinguishable from zero.
You're essentially saying that the error bars on that effect size are big. They are. But they're still centered on zero.
The evidence they had was of such low quality that no solid conclusions could be made from it. What they found in the research may not reflect reality. They are explicit about this and stress the need for better research.
> "There is uncertainty about the effects of face masks. The low to moderate certainty of evidence means our confidence in the effect estimate is limited, and that the true effect may be different from the observed estimate of the effect...There is a need for large, well‐designed RCTs addressing the effectiveness of many of these interventions in multiple settings and populations, as well as the impact of adherence on effectiveness, especially in those most at risk of ARIs."
They admit that they were unclear about it and later were even more explicit.
"Given the limitations in the primary evidence, the review is not able to address the question of whether mask-wearing itself reduces people's risk of contracting or spreading respiratory viruses."
The review is not able to "address the question" let alone conclude anything about the impact of mask wearing. The review is inconclusive.
> The evidence they had was of such low quality that no solid conclusions could be made from it.
OK, fine. If I grant this (I don't, but let's run with it...), it means the following is also true: we mandated something based on such low-quality evidence that no solid conclusions could be made from it.
The basic problem is whether the data says masks don't work, or says that people aren't consistent enough in wearing masks.
I've seen it directly--one woman putting on a mask when I approached. The thing is she had been hiking near the back of the pack in a group that got together for the hike. She was at a far higher risk from being downwind of her group (this was not a family bubble) than of me being off to the side.
I can basically guarantee nobody there was experiencing any appreciable symptoms (10,000' up, miles from the cars--not something you're doing with any sort of respiratory infection) but most Covid spread is presymptomatic.
A solo hiker masking when someone approaches makes sense (and is what I did pre-vaccine), but not masking with your group but masking for a stranger? That's merely an illusion of safety and why masks "don't work".
There's also the problem that the Cochrane data included mostly studies of things other than Covid--when you go over their own data only looking at Covid you do see some benefit. Note, also, the pooling of masks and respirators--we already know masks do little against the Omicron variants. Respirators or don't bother.
Cochrane messed up badly in this case by looking at the wrong thing. I'm reminded of the BMJ study showing zero safety benefit from parachutes when jumping from an airplane.
I would like to point out what “makes sense” to people rarely reflects the underlying fluid dynamics at the relevant scales. Couple that with a poor understanding of just how many particles one infected person emits and it’s clear masks as worn are very ineffective for the vast majority of people.
Yes, the masks didn't work. Now everybody should know it.
First of all, they were using paper mouth shields or adidas branded useless cloths, not masks.
But even the dumb fcks using real n95 mask, i see people everywhere touching the mask from outside (where the viruses should be stopped if the mask works) and then touching everything else. And when coughing opening the mask and coughing inside the palm...
First, some laws probably don't have any positive impact.
Second, there's a difference between accurately summarizing trial results and extrapolating that to the impact of a new law. If there was a death penalty for not wearing masks, perhaps compliance would be better than in the trials and an effect would be shown. This doesn't mean that the trial analysis is wrong, you just can't draw a conclusion about the law from the trial data.
Third, laws have multiple purposes including Justice and Punishment. Some murderers might have zero chance of re-offending but we still want to punish them as a matter of Justice, not because it makes Society safer.
I generally think laws should be codifications of societal norms. Which also implies that as societal norms change so should laws.
So even things such as murder which people do and we don't want should be codified as illegal. But even if nobody committed murder anymore it should still be illegal as its against societal norms.
Point was that some questions are not about law. Im sure you are not going on red just because you could get fined for it.
But also, you'll be fine to go on red in the middle of night, where noone is around. Personal responsibility is unfortunately removed by centralised regulations and laws. Thats the problem.
In reality things are complicated and one principle[1] cannot account for all situations, so we deal with things differently as they come up. Murder happens to be an extremely old problem; public health is also, but knowledge of microbes and infection mechanisms are brand new, so we are still figuring it out.
[1] "personal responsibility" makes little sense as a moral catch-all when ignoring your own health can cause other people problems
- ...ignoring your own health can cause other people problems"
How much of Netflix cause health problem for you? What about food? How much of junk food are you eating? Or maybe we should ban tabaco and alcohol. Or profesional sport. All of that is potential threat for your health. Being overprotective could damage your mental health... etc.
Your comparisons between issues in modern cultural and political concepts are fascinating. Please tell me how overeating, obesity, personal addictions, competitive athletics and media consumption are related to microbial infection vectors so that I can write a definitive thesis about externalities and how they don't exist because I want to live in a libertarian fantasy world.
I will make a comparison, tell me how you find it: "Dumping waste into the river shouldn't be illegal because you dump your waste in your toilet every day and it goes to the river."
Does it sound reasonable? Sure. But I haven't defined scope and I haven't defined effect and I haven't even defined what 'waste' is; I just made up two scenarios which could have similar outcomes and then called it day -- but if you actually care about what happens to the world you need to get a little more detailed than writing silly grandiose political statements and making non-sensical metaphors comparing indicting someone for murder with crafting public health policy.
I'm mass transit where masks will required, most of the people wore the masks covering their chin. I believe the research is accurate and that saying that masking up more people doesn't work because they won't wear them properly
Also, while this study was inconclusive as to whether masks help prevent covid, it doesn't mean that all studies are inconclusive.
For example, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8768005/ is "a detailed performance evaluation of the mask is studied from an engineering point of view," which aim to look at how the physics of N95 masks hold up against covid. What the physics shows is that N95 filtration helps block covid particles.
Mouthwash is typically alcohol based. Alcohol is a pretty good disinfectant in general.
But it's efficacy will really only be decent while it's in your mouth. Once it gets diluted past a certain point, it's not going to be doing anything. You'd probably have similar results with vodka.
I know doctors who recommended drinking whiskey early in the pandemic for that reason (and also the usual reasons people dealing with trauma reach for whiskey)
No, that was a misinterpretation of the review in the Covid-skeptic sphere. Cochrane have had to issue a statement to clarify : https://www.cochrane.org/news/statement-physical-interventio...
tl;dr : half of the people given masks in these studies didn't wear them consistently or at all, dragging efficacy results down.