# Do Masks Work?



## Alligatorob (Oct 17, 2021)

I have been thinking about this for a while and after reading Squatting dog's post on another thread, copied below, began doing a bit of my own online research.

In the interest of full disclosure I have always believed masks helped and have supported mask wearing.  This has been based on my background as an engineer  who has studied filtration, my non-expert understanding of the Covid virus transmission process, and gut feelings.  Reading Squatting dog's post and looking into his references made me decide I needed to do more research.  This research has changed my mind a bit, I still think mask wearing helps, but maybe not so much as I once did.

In summary what I believe I have found is good evidence that mask wearing does help reduce transmission rates.  Not as much as I had thought, but there does appear to me to be some benefit.  In doing the research I tried to stick to peer reviewed epidemiological studies.  I believe epidemiological studies are best as they look at actual population level transmission rates and that's what matters.  The problem with epidemiological studies is that they are expensive and difficult to control.  You need to look at a lot of them to gain some idea of consensus.  Here are a few of the references I looked at and what they said, my research was by no means complete, lots more out there than I have been able to absorb.

_*The Impact of Community Masking on COVID-19: A Cluster-Randomized Trial in Bangladesh *_A study of 342,126 adults that found mask wearing reduced Covid by 9.3% not a huge reduction, but something.
https://www.poverty-action.org/site..._RCT____Symptomatic_Seropositivity_083121.pdf

_*Face masks: what the data say*_ an article in the prominent journal Nature.  After reviewing "_publicly available daily county-level data of confirmed COVID-19 cases from March 25 through May 21.20 The data covered all states plus Washington, D.C., and the analytical sample included 2,930 unique counties plus New York City"_ that found, in part: "_US states mandating the use of face masks in public had a greater decline in daily COVID-19 growth rates after issuing these mandates compared with states that did not issue mandates._"

Note the "Reference period" refers to the time when the mask requirements went into effect, to the left of the red dashed like was before, to the right after.
https://www.nature.com/articles/d41586-020-02801-8 and https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818

_*Mask adherence and rate of COVID-19 across the United States*_ found:
"_In conclusion, we show that mask wearing adherence, regardless of mask wearing policy, may curb the spread of COVID-19 infections. We recommend renewed efforts be employed to improve adherence to mask wearing._"
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249891 

A study of coronavirus mortality in 200 countries: _*Association of Country-wide Coronavirus Mortality with Demographics, Testing, Lockdowns, and Public Wearing of Masks*
_
https://www.ajtmh.org/view/journals/tpmd/103/6/article-p2400.xml#container-33902-item-33911 

This one is a media piece, I include it only because it provides links to a lot of good relevant peer reviewed papers: 
https://www.kxan.com/news/coronavir...-scientific-studies-that-explain-why-they-do/

I also found some evidence that masks can reduce the viral dose, reducing Covid severity.

_*Another Explanation for Why Cloth Masks Reduce COVID-19 Severity*_" https://jamanetwork.com/journals/jama/fullarticle/2777695
_*Masks Do More Than Protect Others During COVID-19: Reducing the Inoculum of SARS-CoV-2 to Protect the Wearer* _https://link.springer.com/article/10.1007/s11606-020-06067-8"
And in the interest of fairness, one that disagrees: _*Confronting the notion that face masks reduce COVID 'dose*_*'* https://www.cidrap.umn.edu/news-perspective/2020/11/confronting-notion-face-masks-reduce-covid-dose
Not disagreeing with Squatting dog so much as trying to present another side to the story.  I do appreciate Squatting dog's thoughtfulness and research. Much more informative than some of the less founded opinions expressed here.  I am guilty of expressing some of those poorly founded opinions myself so not being critical here either.  



squatting dog said:


> *Masks don’t work.* At least a dozen scientific studies have shown that masks do nothing to stop the spread of respiratory viruses.
> 
> One meta-analysis published by the CDC in May 2020 found _“no significant reduction in influenza transmission with the use of face masks”_.
> Another study with over 8000 subjects found masks _“did not seem to be effective against laboratory-confirmed viral respiratory infections nor against clinical respiratory infection.”_
> ...


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## win231 (Oct 17, 2021)

IMO, Dr. Fauci's flip flopping on the mask issue is what did it for me.  When the mask mandate was being considered, he said not to bother; they're useless.  Then he said what he was told to say & said masks protect. 
He's as "educated" as any medical person can be.  He told the truth the first time.


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## dseag2 (Oct 17, 2021)

Wear your masks or not.  Not my problem.  Never mind Covid.  I've had it already and I've been vaccinated.  I go to the gym and the grocery store and wear my mask.  I haven't caught a cold in 2 years.  I also don't plan on catching the flu, which is expected to be pretty severe this season.  Maybe look beyond the immediate issue.


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## win231 (Oct 17, 2021)

Yes, masks work.  I can laugh at people while I'm shopping & they never know it.


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## Alligatorob (Oct 18, 2021)

It's interesting, sound like Win is pretty negative on masks and yet probably wears one more often than I do.  I guess we just go with the crowd, almost no one here wears a mask anymore.  When I was in New Orleans masks were much more common, I wore one but didn't much like it.  


dseag2 said:


> I haven't caught a cold in 2 years


Same here, do you attribute it to masking and social distancing?


win231 said:


> IMO, Dr. Fauci's flip flopping on the mask issue is what did it for me.  When the mask mandate was being considered, he said not to bother; they're useless.  Then he said what he was told to say & said masks protect.
> He's as "educated" as any medical person can be.  He told the truth the first time.


Don't think I would call what he did a lie, so much as poor judgment.  Early on there was little evidence that masks worked, there was little evidence one way or the other.  With time as more evidence has become available it appears (to me anyway) that masks probably do have some benefit, but its limited.  So a mind change isn't in appropriate.  However his job was advising the public and the public needs clear and consistent advise.  On that I think he failed.  Nothing wrong with saying we are recommending masks based on limited data and an abundance of caution.  

I agree he is an educated medical professional, certainly more than I am.  I have zero medical education.  However I think Fauci spent much of his career as an administrator and spokesperson, not a practicing medical professional.


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## win231 (Oct 18, 2021)

Alligatorob said:


> It's interesting, sound like Win is pretty negative on masks and yet probably wears one more often than I do.  I guess we just go with the crowd, almost no one here wears a mask anymore.  When I was in New Orleans masks were much more common, I wore one but didn't much like it.
> 
> Same here, do you attribute it to masking and social distancing?
> 
> ...


Every lie is often called _"Poor Judgement_" when someone doesn't like what the lie reveals about that person's character.
As for my mask wearing, I wear mine when shopping because it's required in my county; not because I think it protects.  I gotta eat.


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## Packerjohn (Oct 18, 2021)

Sure masks work if you are coughing your lungs out or trying to "French Kiss" someone at your local grocery store.  Other than that, what is the point?  I haven't heard anyone cough in the last 19 months at any grocery store I have been to.  Guess I have been lucky.  Maybe where you live everyone is coughing and coughing so masks are a pretty good idea.


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## Lawrence (Oct 18, 2021)

I believe that masks help, my prefered way is to double mask. I wear a paper mask and over it I wear a cloth mask. The cloth mask I have washed previously leaving some soap in the cloth and then I let it dry thorougly. My idea about this is that when I breathe through the cloth mask the moisture from my breath will cause the soap to become moist. Then hopefully the soap molecules will attract any viruses or bacteria thus rendering them inactive.


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## squatting dog (Oct 20, 2021)

win231 said:


> IMO, Dr. Fauci's flip flopping on the mask issue is what did it for me.  When the mask mandate was being considered, he said not to bother; they're useless.  Then he said what he was told to say & said masks protect.
> He's as "educated" as any medical person can be.  He told the truth the first time.


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## Harry Le Hermit (Oct 20, 2021)

Back before covid, my wife and I dined out a couple of times a week. Sometimes with other couples, but we started shying away from some of these couples. Not that they were bad people, but habitually talked with their mouths open, chewed with their mouths open, etc. Food particles and saliva going airborne across the table, spreading whatever virus they may have had. Spitting on others is simply not right, imo.

While I would prefer such folks put a sock in it, wearing masks does decrease the spread of any virus.


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## squatting dog (Oct 21, 2021)




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