Comment by eric_b | Hacker News Reader

Comment by eric_b | Hacker News Reader

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I mean, did you even read it? It is anything but definitive.

"In this narrative review, we develop an analytical framework to examine mask usage, considering and synthesizing the relevant literature to inform multiple areas"

So it's an analytical framework.... let's read on

"Randomised control trial evidence that investigated the impact of masks on household transmission during influenza epidemics indicate potential benefit, although we should be careful of assuming these results will transfer to SARS-CoV-2. In particular, influenza has an R0 (the basic reproduction number) of 1.4 (21) whereas SARS-CoV-2 has an R0 of 2.4 or more"

So they couldn't find an RCT about COVID specifically, and they're not confident prior studies will apply.

And really the nail in the coffin:

"There are currently no studies that measure the impact of any kind of mask on the amount of infectious SARS-CoV-2 particles from human actions"

Like... this is not a good study, or even worth talking about further.

[Edit: Perhaps those wielding the downvotes would care to elaborate on why my analysis of this study is wrong? Or is it just more gut feels? What a joke.]

The issue is that you're breaking the site guidelines. If you want to present your analysis of studies in a way that doesn't do that, that would be much better. Not destroying the ecosystem is more important than being right.

We detached this subthread from https://news.ycombinator.com/item?id=28700178.

Try https://med.stanford.edu/news/all-news/2021/09/surgical-mask... then

Abstract: https://www.poverty-action.org/study/impact-mask-distributio...

Actual paper: https://www.poverty-action.org/sites/default/files/publicati...

Try this one, from a thoughtful MD who tries to follow the science:

https://sebastianrushworth.com/2020/11/19/covid-19-new-evide...

Except the intervention in study Rushworth cites wasn't a mask mandate. It was "Encouragement to follow social distancing measures for coronavirus disease 2019, plus either no mask recommendation or a recommendation to wear a mask when outside the home among other persons together with a supply of 50 surgical masks and instructions for proper use."

According to https://www.acpjournals.org/doi/10.7326/M20-6817, the website for said study: "A systematic review of observational studies reported that mask use reduced risk for SARS, Middle East respiratory syndrome, and COVID-19 by 66% overall, 70% in health care workers, and 44% in the community"

So masks themselves are effective, but only when people actually use them correctly.

According to the conclusion of the paper you just referenced,

Our results suggest that the recommendation to wear a surgical mask when outside the home among others did not reduce, at conventional levels of statistical significance, the incidence of SARS-CoV-2 infection in mask wearers in a setting where social distancing and other public health measures were in effect, mask recommendations were not among those measures, and community use of masks was uncommon. Yet, the findings were inconclusive and cannot definitively exclude a 46% reduction to a 23% increase in infection of mask wearers in such a setting. It is important to emphasize that this trial did not address the effects of masks as source control or as protection in settings where social distancing and other public health measures are not in effect.

So some mild effect for surgical masks they think (though the intervention group did more social distancing than the control group as well, hard to suss out the impact of that).

But then they say this:

"while cloth masks clearly reduce symptoms, we cannot reject that they have zero or only a small impact on symptomatic SARS-CoV-2 infections"

Not exactly a slam dunk.

So you agree that surgical masks have a benefit now?

If you read my comment thoroughly, I was talking about cloth masks. That link you posted is really only interesting as far as surgical masks.

The surgical mask effect is certainly interesting, but they couldn't de-correlate the effect from increased social distancing in the intervention arm. Certainly that seems just as likely to make a difference if not more so eh?

So I'm left where I started: Nothing of consequence about cloth masks, and a mild un-corroborated effect from surgical masks in a country that's about as different from the US as I could imagine.

I wouldn't base public policy on that study, that's for sure. I have no problem if people want to wear masks, go for it. But mandates? I have a higher bar than you to infringe on personal freedoms I guess.

It's important to know what is meant by "surgical" masks. Some of these have an electrostatically blown fiber inner layer which is an electret. Although the fit is not as good as an N95 respirator, the basic filter is comparable to an N95 or at least a KN95. The typical "procedure" mask that civilians wear doesn't have that yet.

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