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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

#11

Post by majormajor »

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 better fit of cloth masks would make them better, but presumably the mask surface of a surgical mask has properties that offset that?

Would be great to see numbers for N95 masks. Intuitively I'd assume they'd be much more effective as they have better fit + higher filtration, but of course, confirmation would be great.

Fits with what we're seeing in Europe such as airlines banning cloth masks, though.

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."

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

#13

Post by douglasisshiny »

exabrial wrote: post #6

This is truly great news, as we've need some controlled studies. However, _mandates_, literally threatening people with police violence, bodily or financial harm, is not the correct way forward. I think the best solution is improved mandates for airflow. It's a lot easier to improve airflow in a building than it is to police and enforce a mask mandate.

>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 reasonable.

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

#14

Post by cfn »

Here is the paper (or one of them, it is not clear after so many links):

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

Bottom line: "The proportion of individuals with COVID-like symptoms was 7.62% (N=13,273) in the intervention arm and 8.62% (N=13,893) in the control arm. Blood samples were collected from N=10,952 consenting, symptomatic individuals. Adjusting for baseline covariates, the 2 intervention reduced symptomatic seroprevalence by 9.3% (adjusted prevalence ratio (aPR) = 0.91 [0.82, 1.00]; control prevalence 0.76%; treatment prevalence 0.68%). In villages randomized to surgical masks (n = 200), the relative reduction was 11.2% overall (aPR = 0.89 [0.78, 1.00]) and 34.7% among individuals 60+ (aPR = 0.65 [0.46, 0.85]). No adverse events were reported."

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

#15

Post by nielsbot »

exabrial wrote: post #6

This is truly great news, as we've need some controlled studies. However, _mandates_, literally threatening people with police violence, bodily or financial harm, is not the correct way forward. I think the best solution is improved mandates for airflow. It's a lot easier to improve airflow in a building than it is to police and enforce a mask mandate.

Why not? It's harm reduction. You're required to wear a seat belt and have car insurance. Cigarette manufacturers are required to put warning labels on their products. Wearing a mask is annoying and unfashionable but not that annoying. Plus, when COVID numbers drop, mask mandates are again lifted.

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

#16

Post by slg »

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…

>It's surprising to me that cloth masks can't even do the 11% of surgical masks.

Just want to add clarification here. The 11% number is the community impact of the programs designed to increase mask usage. It is not the effectiveness of a mask on an individual level. That number will be much higher since as you said a number of people didn't/don't comply at a societal level.

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

#17

Post by kongin »

exabrial wrote: post #6

This is truly great news, as we've need some controlled studies. However, _mandates_, literally threatening people with police violence, bodily or financial harm, is not the correct way forward. I think the best solution is improved mandates for airflow. It's a lot easier to improve airflow in a building than it is to police and enforce a mask mandate.

Ban open offices. The simplest solution that solve so many problems.

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

#18

Post by dragontamer »

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…

I think most of us got cloth masks with the full expectation that they were worse than proper PPE from hospitals (be it surgical masks or N95 masks).

I'm not sure if people remember: but there was a shortage of masks of all kinds in March 2020. Cloth masks were the only thing we could get, and we all knew they were kind of crap (a lot of us were using coffee filters stapled onto the masks to increase its effectiveness).

------

Now that the N95 shortage is over (at least, I'm buying N95 duckbills at $1 each these days), I think its time to seriously consider using N95 in the public. At least in America, where we seem to have suddenly a huge influx of N95 availability this year.

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

#19

Post by barbazoo »

input_sh wrote: post #9
chitowneats wrote: post #4

From Martin Kulldorff, esteemed (though contrarian) Harvard Med epidemiologist: "Odd that mask advocates are excited by this study. As a vaccine advocate, I would be horrified if a vaccine trial showed 11% efficacy. Based on the 95% confidence intervals, we do not even know if surgical mask efficacy is more than 0%." https://twitter.com/MartinKulldorff/status/14332026511062016...

And then see this response to that claim by one of the study's authors: https://mobile.twitter.com/Jabaluck/status/14331294449405992...

which seems to have been deleted in the meantime

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

#20

Post by mullen »

exabrial wrote: post #6

This is truly great news, as we've need some controlled studies. However, _mandates_, literally threatening people with police violence, bodily or financial harm, is not the correct way forward. I think the best solution is improved mandates for airflow. It's a lot easier to improve airflow in a building than it is to police and enforce a mask mandate.

This is naive. There is a significant portion of the population that are not going to cooperated with health safety protocols unless there is a real chance of them going to jail or getting a fine.

We're talking wearing a mask and saving lives.

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