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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

#161

Post by slg »

timr wrote: post #51
slg wrote: post #16

Earlier quoted context omitted.

>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.

> That number will be much higher since as you said a number of people didn't/don't comply at a societal level. ...or it will be lower. The study confounds the effects of distancing and mask-wearing. Distancing was higher in the surgical mask cohort. Also, as others note, the confidence interval for the surgical mask group overlaps zero. You can't rule out that the observed effect is due to chance.

From the study:

>The intervention increased proper mask-wearing from 13.3% in control villages (N=806,547 observations) to 42.3% in treatment villages (N=797,715 observations)... Physical distancing increased from 24.1% in control villages to 29.2% in treatment villages

Mask wearing increased 218% while distancing increased by 21%. I agree this is not proof specifically about masks, the study is about specific public policy programs and not mask wearing in general, but it certainly seems like masks wearing is the biggest contributor to the reduction seen.

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

#162

Post by mdp2021 »

vondur wrote: post #152
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…

Am I misunderstanding this from the paper: "The proportion of individuals with COVID-like symptoms was 7.62% (N=13,273) in the intervention arm and 8.62% (N=13,893)" That really seems like a pretty small overall difference in the two groups in terms of those getting infected.

Because the the compliance increase in the «intervention arm» was +30%, not "total compliance". +30% compliance → -11% infections.

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

#163

Post by RHSeeger »

learc83 wrote: post #97
betwixthewires wrote: post #60

Earlier quoted context omitted.

It's a pretty solid gotcha.

It's a terrible gotcha. It's only effective on people who already agree with you. Imagine a town council meeting where someone is proposing a $25 fine for crapping on the sidewalk. And a libertarian pops and screaming "You're saying you want to use violence up to and including murder to keep our sidewalks clean!" Again technically there is a hypothetical chain of causality from sidewalk crapping fine to bodily harm/m…

> You're saying you want to use violence up to and including murder to keep our sidewalks clean!

Because that's what you _are_ saying. Laws are enforced by the police, and they are able to be enforced by the police because the police are legally able to use force. I do not understand what other view there is to take on the issue. In my mind, it's not an opinion, it's a fact.

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

#164

Post by dpweb »

acranox wrote: post #48
majormajor wrote: post #28

Earlier quoted context omitted.

Could you share a link for $1 N95's? That's better than I've seen. I've already moved to this approach myself, it's an increase in cost that I'll gladly take for increased protection. Just waiting for government and businesses in the US to catch up. It was definitely hard to find the good stuff at first - and I was much more reclusive as a result too - but yeah, things have changed. I wish people wouldn't respond to…

https://www.homedepot.com/p/3M-N95-Particulate-Performance-D... Home Depot sells this 20 pack for $24 from 3M. That’s $1.20 each.

Count your masks. My box of 10 3M masks (closed not taped shut) from Home depot only had 9 in it.

The told me I can gladly travel 30 min back to the store and wait in line for a refund. No thanks.

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

#165

Post by WarOnPrivacy »

toomim wrote: post #40
majormajor wrote: post #28

Earlier quoted context omitted.

Could you share a link for $1 N95's? That's better than I've seen. I've already moved to this approach myself, it's an increase in cost that I'll gladly take for increased protection. Just waiting for government and businesses in the US to catch up. It was definitely hard to find the good stuff at first - and I was much more reclusive as a result too - but yeah, things have changed. I wish people wouldn't respond to…

You can get the awesome 3M Aura used in hospitals for $2.20. These are great: https://www.ebay.com/itm/224332977653?_trkparms=amclksrc%3DI...

I keep reading this as >You can get the awesome 3M Aura used

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

#166

Post by YZF »

dragontamer wrote: post #18
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…

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 effectivenes…

What about the amount of waste/garbage this creates? It's already a problem finding random discarded masks all over the place. We need a reusable/washable N95 class mask.

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

#167

Post by hncurious »

belorn wrote: post #124

Its interesting that the article do not mention a rather interesting finding in the study. For the age groups of Why aren't masks effective to reduce the spread for that age group? The discussion part of the study don't explore it. Is the distancing behavior of people aged 50 or higher different than those below? I would like to see further studies being done on the younger demographic in order to explain why the dat…

They did report that physical distancing increased in villages that were given masks, so that may explain it. Unfortunately they didn't untangle that effect? How do we know to what degree it was the masks vs increased distancing?

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

#168

Post by WarOnPrivacy »

helge9210 wrote: post #157
jasonlaramburu wrote: post #131

Earlier quoted context omitted.

Anyone who is legitimately concerned about COVID transmission should be wearing at least a KN95 mask. It would be interesting if the study had compared effectiveness against higher performance masks and respirators.

I totally agree. On the other hand I would like to opt out of this exercise, since I'm totally not concerned with COVID.

I know a place where workers keep having to quarantine following covid reoccurrences. Looking for a job?

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

#169

Post by RHSeeger »

rafaelero wrote: post #108
tomjen3 wrote: post #95

Earlier quoted context omitted.

It isn't a gotcha, it is just thinking through the second, third, etc order of what you are proposing.

Which it is totally worth it when the counterfactual would be a dumbass playing loud music every night. Is there another solution to this that doesn't require ultimately the use of force?

There are plenty of options in between "person breaks law" and "person is the subject of lawful violence". They include things like warnings, fines, and the like. However, all _those_ things are backed by the possibility of the end result being violence. All of them follow a path of either the person doing what they're supposed to... or violence. The only variables are the number of steps until you get to violence... or the person doing what they're supposed to... or the rest of the society deciding to change the definition of "supposed to do".

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

#170

Post by YZF »

clairity wrote: post #134
timr wrote: post #51

Earlier quoted context omitted.

> That number will be much higher since as you said a number of people didn't/don't comply at a societal level. ...or it will be lower. The study confounds the effects of distancing and mask-wearing. Distancing was higher in the surgical mask cohort. Also, as others note, the confidence interval for the surgical mask group overlaps zero. You can't rule out that the observed effect is due to chance.

yes, distancing does most of the work in most common situations. a mask can only work when conversing closely for a time indoors. otherwise masks do nothing, no matter the filtration rate of the mask, because there's nothing to filter in the first place. distancing is a more universal and sensible mitigation (we're distanced from nearly all of the world population all the time). this is why mask mandates, as currentl…

Aren't you sharing air with others in any common indoors space?

I thought that was the whole aerosols debate that's basically settled by now, i.e. virus can stay suspending in the air for extended periods. With the Delta variant's characteristics this is also a much bigger problem (i.e. the same indoor space that might have been ok is no longer ok).

There were early studies with the less infectious variants that showed how people situated far from each other in indoors spaces infect each other.

So the mandate for masking in any common indoor space seems to make a lot of sense.

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