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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

#81

Post by slg »

timr wrote: post #67
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…

They did all of those things, but this paper is about the effect of mask-wearing (surgical vs. cloth vs. none) on the rate of symptomatic seroprevalence in the groups. Kuldorff is right, and is just stating the top-line numbers from the paper.

>Free mask distribution and promotion reduced the proportion of people who reported COVID-like symptoms on average by 11 percent, which was driven mainly by the effects of surgical masks. Villages where cloth masks were distributed experienced a 5 percent reduction in symptoms, while villages where surgical masks were distributed saw a reduction of 12 percent. About a third (40 percent) of those who reported COVID-19 symptoms agreed to have their blood tested for SARS-CoV-2. On average, researchers found a decrease of symptomatic SARS-CoV-2 infections of 9 percent. This reduction was higher in villages that wore a surgical mask (11 percent) and in these, among individuals aged 60+ (35 percent).

It is measuring the effectiveness of the public policy and comparing how it differs when the masks distributed were cloth versus surgical. There is nothing in this report about the effectiveness of masks on an individual level.

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

#82

Post by slg »

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.

>Hmm, are you suggesting that those public policies might have had an impact on covid transmission that wasn't mediated through mask-wearing?

That wasn't the intention of my comment, but yes that is also true. As the article notes:

>"In the intervention villages, they also saw a slight increase in physical distancing in public spaces, such as marketplaces."

My original comment was more directed at the fact that these public policies are not 100% effective in getting people to wear masks. Therefore the society reduction of 11% is not comparable to the vaccine efficacy numbers which are measured at an individual level. If we measured vaccine efficacy numbers using this societal approach, the numbers in the US would be abysmal considering our active case numbers are quickly approaching the peak of the pre-vaccine waves.

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

#83

Post by nabakin »

fasteddie31003 wrote: post #77

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.

Do you have a good source on this?

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

#84

Post by GeekyBear »

mhb wrote: post #74

Why didn't they test N95 masks?

>Why didn't they test N95 masks?

The difference between a cloth mask and an n95 mask when dealing with an airborne virus has been tested.

>Studies that have been done show that if an individual might get infected within 15 minutes in a room, by time and concentration of the virus in the room, add a face cloth covering you only get about five more minutes of protection.

On the other hand if you use the n95 respirators and fit them tight to your face, you can actually spend 25 hours in that same room and still be protected.

https://www.pbs.org/wnet/amanpour-and-company/video/do-masks...

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

#85

Post by fasteddie31003 »

nabakin wrote: post #83
fasteddie31003 wrote: post #77

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.

Do you have a good source on this?

https://www.science.org/content/article/having-sars-cov-2-on...

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

#86

Post by gbjw »

nabakin wrote: post #83
fasteddie31003 wrote: post #77

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.

Do you have a good source on this?

https://www.science.org/content/article/having-sars-cov-2-on...

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

#87

Post by Scoundreller »

nokcha wrote: post #45
dragontamer wrote: post #30

Earlier quoted context omitted.

That "K" means that my ears hurt after 2 hours though. Going for full N95 means that the strap goes all the way around my head and is way more comfortable for extended use (ex: airplane rides or whatnot)

There are also KN95 masks with headband straps instead of earloop straps. E.g., a web search for "Powecom KN95 Respirator Headband Style".

Also 3M 9502+ KN95 which was subsequently NIOSH N95 approved (but you had to pay more if you wanted the ones stamped for the US market).

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

#88

Post by [deleted] »

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?

[deleted]

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

#89

Post by Scoundreller »

fasteddie31003 wrote: post #77

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.

I’m not quite at that point of “fuck it, I’m vaccinated, come at me”, but I have to travel soon and the country I’m transiting through (Iceland) now requires a test.

I’m nervous about it because I’m vaccinated, so I very well could have a mild infection and not know it, and get denied boarding and quarantined at home.

At least it’s an antigen test and those miss most non-symptomatic infection anyway.

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