This is blatant misinformation. Masks work. We've known this for over a century. Using masks to control respiratory disease is one of those cool public-health hacks that almost sounds too good to be true, but if enough people do it, the virus stops burning through the population.
https://en.wikipedia.org/wiki/Face_masks_during_the_COVID-19...
You aren't so much being "censored" as just downvoted into the oblivion where a factually, empirically, and dangerously wrong statement like "We have essentially no evidence that non-respirator masks, in the hands of the public, does anything at all" belongs.
Your link is a website made by a guy who teaches online ML classes, has no relevant expertise in science or medicine, and blatantly mischaracterizes the papers covered by the CEBM link.
I suggest you read the evidence I’ve provided, before concluding the matter is settled.
We have tons of evidence. Countries with high mask compliance have done a much better job of containing the virus. It's difficult to determine if it's causative or coincidental so it's not conclusive, but it certainly is evidence.
You do realize that's an extremely important distinction. A shitty mask in use by a medical professional will do more "social" good than a good to great mask used by a moron (the general public).
A way to prove that, how do you wash your hands. Unless you're a medical professional or know of one, you've probably been doing it wrong to prevent the spread of germs. Look up how a surgeon is supposed to wash their hands. One important note, put your hands up so the water drips down your arm instead of to your fingers. Germs flow with the water, so the idea is, they can get locked into the creases in your fingers if they drips down there. People just "wash their hands longer"... which is not that effective to the proper way of doing it.
The masks... good God... the people who yell at folks not wearing masks typically have their nose exposed.
But hey, there's then the fact of infected moisture droplets on your clothing. Depending on the study, it can live for some amount of hours. Especially after it was found to be airborne anyways. A tshirt being pulled over your face with covid on it, that's okay?
Look, it's more that this whole thing is far more complicated than the general news has us believe. Perfect action to stop the spread by "the general public" is sort of like wishing for peace on Earth. Yea, we can do our little bongo circles and poster signs with glitter, signing whatever stupid treaty in random city... there will still be war. There will still be tons of people spreading whatever contagion because of not understanding the fundamentals of germ prevention. Which no one will ever bother learning or doing. To be fair, the whole process of perfect prevention or at least truly effective is super difficult and requires constant dedication without fail.
Yes, it'd be nice to get R to 0. But any number below 1 is good enough.
And don't get me wrong, I technically want to be wrong. But science and human nature butt heads. People are human, perfect lab conditions don't imitate human actions that well. Relying too much on lab condition results and ignoring the idea of, "How will Joe Schmoe fuck this up?" means you wasted lab time.
Hell, how many UI folks here? Or any programmers that have to deal with user testing? In your perfect locked away testing, everything is "perfect". Admit it. You think you solved all the ways users will screw up. Then it goes out into the wild, only to find out how incredibly stupid humans are. How many times have you said, "That's not the way you're supposed to use that!" regarding software and a random person?
Why is the HN community so willing to think this behavior doesn't apply outside computers?
If you think there is additional evidence that they have not covered, cite it.
“Countries with high mask compliance” is not a definable parameter. Japan was held up as a “mask-wearing country”, but is currently in the midst of a major outbreak. Hawaii is locked down again. Singapore has had recurrent outbreaks, despite widespread mask use. Sweden and the Netherlands do not require masks, and have brought their epidemics under control.
Any attempt to draw conclusions based on what happens to a country after passing a mask rule, is an exercise in post hoc fallacious reasoning.
"We have essentially no evidence"
And then you provided links that contain evidence. It may not be persuasive or conclusive, but there is evidence.
We have some evidence that they’re almost completely ineffective in the hands of the general public, some that they may be actively harmful (the only RCT ever performed with cloth masks showed that those who wore cloth masks were 13 fold worse off than those in the control arm), and some studies that show modest positive effects when N95 respirators are used by doctors in hospitals.
If we are discussing “face covering” rules as enacted by governments today, which include everything from bandanas to paint respirators, then no, there is no supporting evidence.
> the only RCT ever performed with cloth masks showed that those who wore cloth masks were 13 fold worse off than those in the control arm
I think you're referring to this study, please confirm: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4420971/
"The aim of this study was to compare the efficacy of cloth masks to medical masks in hospital healthcare workers (HCWs)"
You misrepresent the study in three critical ways:
1. You fail to note that the "control arm" was use of medical-grade masks, as opposed to no mask at all.
2. The study explicitly did not include a no-mask arm, as that would be ethically problematic. Their "control" arm actually consisted of "standard practice, which may or may not include mask use. Standard practice was used as control because the IRB deemed it unethical to ask participants to not wear a mask". The increased infection risk of cloth masks could be due to harm caused by cloth masks, benefit conferred by medical masks, or most likely both. As the authors point out, this study cannot determine this.
3. The study focused on healthcare workers, whereas the question at hand is whether convincing big portions of the general population to wear cloth masks in public enclosed spaces works.
Fun fact: the same authors of this study have submitted a follow-up article which is available for early release: https://wwwnc.cdc.gov/eid/article/26/10/20-0948_article
They write that "wearing cloth masks should not be mandated for healthcare workers. In community settings, however, cloth masks may be used to prevent community spread of infections by sick or asymptomatically infected persons, and the public should be educated about their correct use."
In other words:
- the mask RCT you referred to doesn't support your agenda of insisting that community use of cloth masks doesn't mitigate the spread of respiratory illness
- the same authors of that study have directly refuted your claims in an upcoming publication
You aren't being downvoted because the left-leaning HN hivemind is reflexively jabbing the down arrow because you're telling them something they don't like. It's because you're flat-out wrong.
> We have no evidence of positive effect.
Demonstrably and categorically false. I'm starting to wonder if you're trolling HN on a Friday morning; if so, congratulations.
If you aren't a troll, please review this body of literature helpfully curated by smart people who give a damn:
1) the study in question had a control arm of voluntary compliance with surgical masks. These are neither “medical grade”, nor was the compliance rate verified.
2) Regardless, it doesn’t matter: cloth masks were significantly more harmful than the control.
3) I agree that we should be careful to discriminate between studies of respirators, masks, “face coverings”, PPE and source control. So you should take the time to actually read the studies that Jeremy Howard cites. You’ll find that nearly all of the studies on masks are for respirators in medical settings, and that (as the CEBM link confirms, if you bothered to read it), the few studies of mask use by the general public have had ambiguous or negative outcomes. It isn’t even close: if you omit the studies conducted in medical settings, there’s almost no evidence for masks at all.
4) The CDC link isn’t a scientific article, it’s a review. Moreover the authors are clear that they are not contradicting their previous findings:
” To our knowledge, only 1 randomized controlled trial (4) has been conducted to examine the efficacy of cloth masks in healthcare settings, and the results do not favor use of cloth masks.”
The authors are explicit that cloth masks are unsupported, possibly harmful, and only to be used as a last resort.
You really should read the links you cite before you make strong claims about what they say.
The paper cited by the nature article does not explicitly consider masks or hand washing. It combines all measures recommended by the Mexican government, and makes a broad assumption about their overall effectiveness:
https://www.sciencedirect.com/science/article/pii/S002555642...
All of the models for handwashing and masks that I am aware of have made blithely optimistic assumptions about their effectiveness. The WHO meta-study of masks, eye protection and social distancing found that masks overall had an odds ratio of 0.33 - and most of that evidence came from N95 respirators, used in hospitals, for personal protection:
https://www.thelancet.com/journals/lancet/article/PIIS0140-6...
We have essentially no evidence that non-respirator masks, in the hands of the public, does anything at all:
https://www.cebm.net/covid-19/masking-lack-of-evidence-with-...
(Edit: as per usual, factual discussion of masks is censored on HN. This is not a political debate! I have provided links to legitimate scientific resources to support all of my arguments. Consider your bias before reflexively jabbing the downvote button.)