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Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

med.stanford.edu

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Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#71

Post by nivenkos »

bsksi wrote: post #56
douglasisshiny wrote: post #13

Earlier quoted context omitted.

>However, _mandates_, literally threatening people with police violence, bodily or financial harm, is not the correct way forward. Maybe I'm missing something, but is this actually a thing? Who in the mainstream proposing police violence, bodily or financial harm? The worst I've heard (in the U.S.) is that a business may not allow you to enter if you're not wearing a mask, which is well within their right and reasona…

In my country you are removed and fined if you are seen indoors or outdoors where you can't keep a distance without a mask. It's when I read comments like yours that I feel so jealous of the US. You don't even know what living where I am is like. For you it's like a place that couldn't possibly exist. :P

> It's when I read comments like yours that I feel so jealous of the US.

And then the same Americans ban you from Reddit if you complain about the lockdowns or forced mask mandates.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#72

Post by Johnny555 »

starik36 wrote: post #53

So am I understanding the study correctly? > Those living in villages randomly assigned to a series of interventions promoting the use of surgical masks were about 11% less likely than those living in control villages to develop COVID-19 The surgical masks are 11% more effective in preventing COVID infection than not wearing masks at all?

That's overall community effectiveness, and with only 50% mask compliance:

“It’s notable that even though fewer than 50% of the people in the intervention villages wore masks in public places, we still saw a significant risk reduction in symptomatic COVID-19 in these communities, particularly in elderly, more vulnerable people.”

And the protective effect was even more pronounced in the elderly:

The protective effect increased to nearly 35% for people over 60 years old.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#73

Post by dragontamer »

kragen wrote: post #39
dragontamer wrote: post #2

> The researchers enrolled nearly 350,000 people from 600 villages in rural Bangladesh Wow. I was about to complain about "small n", but... an experiment of this size is not small at all. Congrats on the researchers on doing such a big study!

Maybe the relevant point is that it needed to be this big to get a P-value of less than .05, since they only got .04 even with 350,000 people. This is dramatically less effectiveness than I was expecting when I was pushing for mask mandates last year, and within a few months it was obvious that masks alone weren't having the large effect I had hoped for. Now we have quantitative estimates of how small the effect was…

When 70% of people weren't affected by the experiment (13% were wearing masks before the experiment started. 60% of people didn't wear a mask after the experiment), then of course the numbers are going to be small.

Seeing a measurable difference when the population only changed from 13% mask to 40%ish mask usage is pretty outstanding IMO.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#75

Post by bsksi »

nivenkos wrote: post #66
douglasisshiny wrote: post #13

Earlier quoted context omitted.

>However, _mandates_, literally threatening people with police violence, bodily or financial harm, is not the correct way forward. Maybe I'm missing something, but is this actually a thing? Who in the mainstream proposing police violence, bodily or financial harm? The worst I've heard (in the U.S.) is that a business may not allow you to enter if you're not wearing a mask, which is well within their right and reasona…

Have you not heard of the lockdowns here in Europe? In Spain we were forced inside for 2 months, and then forced to wear masks at all times in public - indoors and outdoors. The police got a free pass to beat and arrest people with the excuse of masks or curfew: https://elpais.com/espana/2021-03-28/la-policia-investiga-a-... I got banned from some subreddits just for posting that, because it's become such a political…

And don't forget that all of this was ruled illegal a year later. All fines reimbursed, but who gives us back the time that was stolen from us?

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#76

Post by gotoeleven »

stolenmerch wrote: post #61
majormajor wrote: post #11

Earlier quoted context omitted.

It's surprising to me that cloth masks can't even do the 11% of surgical masks. Which isn't much, but surgical masks are non-optimal for many reasons. Not to mention that this doesn't seem the same as "while wearing a surgical mask you only get 11% increase in protection" but is a population-level thing. There was still non-compliance that presumably lowered the efficacy. I would've intuitively guessed that the bette…

> The great incoherent idiocy of anti-* Americans on the issue of masks has always been that they say "cloth masks are ineffective" and propose a solution of "do nothing" instead of "get effective masks." I think the "no nothing" solution has more to do with a desire to return to normal than it is a refusal to "get effective masks" and just wear them forever or until some agency says not to anymore. There is a valid…

Wearing a proper mask that actually substantially reduces the chance of contracting or spreading covid is uncomfortable. As many of us have been saying from the beginning (including the CDC initially!) the cloth masks are just the medical equivalent of TSA security theater. Right now they just function as a little badge to indicate which "team" you're on.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#77

Post by fasteddie31003 »

I was militant pro-mask when I was unvaccinated. Now that I'm vaccinated and have no comorbidities, I'm OK with being exposed to COVID-19. In fact, I want to have a mild case of COVID-19 to get natural immunity. Natural immunity seems to be more effective than the vaccine for long lasting immunity.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#79

Post by Volundr »

kragen wrote: post #46
slg wrote: post #8

Earlier quoted context omitted.

Except that was not what was tested. Here is what they did: >No-cost free masks distribution - One-third of the intervention villages received a cloth mask and two-thirds of the intervention villages received a surgical mask[5] during household distribution and distribution at marketplaces and other public locations weekly or every fortnight. Masks were also distributed at mosques on three Fridays during the first fo…

Hmm, are you suggesting that those public policies might have had an impact on covid transmission that wasn't mediated through mask-wearing? For example, having the imams discuss the importance of mask-wearing might discourage people from going to Friday prayers? That seems unlikely but conceivable.

Not really. What's being suggested is that what's being tested is both societal compliance combined with mask effectiveness. To dramatically over simplify, let's assume we have a population of 10, none of them mask wearers. Let's also assume masks are 100% effective at preventing Covid infection. These measures convince only 1 person to wear a mask.

In the control group (no advocacy) 10/10 are infected. In the study group 9/10 are because that one person wore a mask. So we've got an effectiveness of 10%, despite masks in our contrived example being 100% effective. The effectiveness is blunted by lack of compliance.

Re: Surgical masks reduce Covid-19 spread, large-scale Stanford study shows

#80

Post by jaclaz »

majormajor wrote: post #11
ch4s3 wrote: post #3

> There were significantly fewer COVID-19 cases in villages with surgical masks compared with the control villages. (Although there were also fewer COVID-19 cases in villages with cloth masks as compared to control villages, the difference was not statistically significant.) This aligns with lab tests showing that surgical masks have better filtration than cloth masks. However, cloth masks did reduce the overall like…

It's surprising to me that cloth masks can't even do the 11% of surgical masks. Which isn't much, but surgical masks are non-optimal for many reasons. Not to mention that this doesn't seem the same as "while wearing a surgical mask you only get 11% increase in protection" but is a population-level thing. There was still non-compliance that presumably lowered the efficacy. I would've intuitively guessed that the bette…

> Intuitively I'd assume they'd be much more effective as they have better fit + higher filtration, but of course, confirmation would be great.

I think that is really hard to say.

IF they are properly fitted (that won't normally be the case).

As I see it (as well intuitively) if the virus is transmitted "directly" by droplets then cloth, surgical or N95 won't make much difference from a clear plastic shield (as we have seen many in hospitals wear, besides the masks), while if it is transmitted by aerosol the filtration capacity changes matters greatly.

Point is whether a (poorly) fitted N95 does actually protect more than a surgical mask.

Since a N95 is "harder" to breath in (as it filters much more), it is possible that a lot more non-filtered air comes from the (poor) fitting gaps.

In my personal case I have (now) a beard and #1 lesson when years ago I was taught how to wear a N95 (actually a FPP2, almost the same as N95) was that you had to be cleanly shaven, and - besides that - I had to try some 5 or 6 different mask models before finding a suitable one (the mask shape need to be suited to your face shape for a proper fit).

This is a pet-peeve of mine, but noone actually wears N95 masks properly: https://news.ycombinator.com/item?id=22728367 https://news.ycombinator.com/item?id=23957506

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