Another Study about Mask Effectiveness

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RikkiTikkiTavi
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Another Study about Mask Effectiveness

Post by RikkiTikkiTavi » Tue Dec 07, 2021 10:33 am

I just ran across this accounting of a study that rated masks versus social distancing:

https://www.dailymail.co.uk/news/articl ... finds.html

I thought I would share how I critique these kinds of articles. First I don't consider an article about a study to be a good source because all articles are going to have the bias of the writer. I want to come to my own conclusions, so I look for the study.

The article did not reveal the study source, but it did reveal a little information about where the study originated, so I used some of that info to search.

Searched for: universities of Göttingen and Cornell facemask study

That gave me this link:
https://www.pnas.org/content/118/49/e2110117118

and hooray - that was the study. Now I can see how they set up the study.

I go in with initial questions:
1. What was the purpose of the study? This is usually expressed in the first part of the study notes:
... it is not clear how exactly the risk of infection is affected by wearing a mask during close personal encounters or by social distancing without a mask...
So that is the focus of this study and the question they seek to answer.

2. How did they conduct the study? This will give us information on whether this was just looking at other studies, doing experiments with live subjects in controlled situation or in real world situation, or other avenues.
To calculate exposure and infection risk, we use a comprehensive database on respiratory particle size distribution; exhalation flow physics; leakage from face masks of various types and fits measured on human subjects; consideration of ambient particle shrinkage due to evaporation; and rehydration, inhalability, and deposition in the susceptible airways.
Okay, so this is not going to actually take measurements from live subjects in real world situations but rather look at controlled lab experimentation. It seems like they had some human subjects, but the environment was controlled.
While our quantitative analysis is limited to typical parameters for SARS-CoV-2, our approach also applies to other parameters and other respiratory infectious diseases. Here we answer the following questions:

• What is the upper bound on SARS-CoV-2 infection risk for near-field exposure?

• How does this upper bound change with the respiratory activities, that is, passive breathing vs. talking?

• How does this upper bound vary with the exposure duration?

• How do the type of face mask and the way it fits to the face affect the upper bound?

• Which intervention strategy, between masking and social distancing, is most effective?
'Upper bound' is how they calculate [ the particles of virus needed to produce and infection x the outward leakage of the mask x the way the environment messes with the virus particles x the inward leakage of the mask x effect on the respiratory tract ] (big ole calculation)
From this information we can see they were taking into account a lot of potential variables. They indeed know that the actual risk of one on one exposure is extremely hard to calculate due to all the variables.
The main idea behind the upper bound is that, if a scenario proves to be safe under the upper bounds defined here, there is no question of its effectiveness under real conditions.
They went through several potential scenarios with people wearing different types of masks, no masks at all and also different lengths of distancing.

3. What was the conclusion of the study?
It was summarized like this:
Our results show that social distancing alone without masking is associated with a very high risk of infection, especially in situations where infectious is speaking. High infection risks are also expected when only the susceptible wears a face mask, even with social distancing. We show that universal masking is the most effective method for limiting airborne transmission of SARS-CoV-2, even when face seal leaks are considered.
I found this study to be very self aware that it was not a 'real world' study. It took careful steps to evaluate in such a way that its conclusions could be valid in real world situations.

This was a very well done study and my summary of it here does not reveal all the in depth information it generated. Even if you are not used to reading studies, you will find it worth the challenge of reading it.

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Z6IIAB
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Re: Another Study about Mask Effectiveness

Post by Z6IIAB » Tue Dec 07, 2021 1:42 pm

A lot of scientists who are part of covid study groups in Brazil are talking about that study on twitter for scientific divulgation to the public! I knew I've seen that study somewhere: https://twitter.com/melmarkoski/status/ ... 7982597131 I think you'll appreciate their tweets (even if they are on portuguese, the google translator works well enough).
Call me Celina. This forum still have a long way to go until it gets filled with its intended public. And I'll do my best to help us reach that goal. I'm a battleaxe, and when you hear my voice it'll be as loud as a thunder and as clear as a blue sky.

Tanagra
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Re: Another Study about Mask Effectiveness

Post by Tanagra » Wed Dec 08, 2021 4:41 am

I live in Japan. Now, I don't want to jinx it, but good gosh, for this entire time as far as I'm concerned Japan has been a textbook case that masking works. To top that, currently it would appear also a textbook case that vaccinating works. And that when you put continued masking together with vaccinating, you get shockingly great results. It does end on this note:
The sense of fear that kept people distanced for a year and a half is fading. And because of that, he thinks the very low infection rate Japan has now will not last.

"We are one to two months behind Europe" he says. "Very soon, we will see another wave developing."
https://www.bbc.com/news/world-asia-59342308

LinguisticTacoXX
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Re: Another Study about Mask Effectiveness

Post by LinguisticTacoXX » Sun Dec 12, 2021 2:57 pm

Tanagra wrote:
Wed Dec 08, 2021 4:41 am
I live in Japan. Now, I don't want to jinx it, but good gosh, for this entire time as far as I'm concerned Japan has been a textbook case that masking works. To top that, currently it would appear also a textbook case that vaccinating works. And that when you put continued masking together with vaccinating, you get shockingly great results. It does end on this note:
The sense of fear that kept people distanced for a year and a half is fading. And because of that, he thinks the very low infection rate Japan has now will not last.

"We are one to two months behind Europe" he says. "Very soon, we will see another wave developing."
https://www.bbc.com/news/world-asia-59342308
I thought Japan was wary of vaccination themselves, but they mask up whenever possible. Did something change regarding the vaccines?

Tanagra
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Re: Another Study about Mask Effectiveness

Post by Tanagra » Sun Dec 12, 2021 9:36 pm

I thought Japan was wary of vaccination themselves, but they mask up whenever possible. Did something change regarding the vaccines?
I did find an article from just about a year ago all about that, actually. https://www.japantimes.co.jp/news/2020/ ... ronavirus/

I can tell you 100% what changed regarding the vaccines. The truth. We in Japan got to watch, because in this modern reality information is available very quickly. We got to watch the surges in hospitalizations and deaths in other countries that occurred immediately after people stopped wearing masks, after lockdowns were lifted, and we also got to watch how these hospitalizations and deaths went down amongst vaccinated.

Here in Japan, since we started with the at-risk groups, the same drop in hospitalizations and death told us it was working. Now, general vaccinations began in July. I got my first shot on July 15th. My second August 19th. I'm one of the lucky ones who had no trouble at all. The numbers of people hospitalized and dying dropped like a stone as vaccinations increased. Tokyo, being one of the most populated cities, has always been our litmus test. Depending on which hoaxer you ask, there are the ones who will tell you that Japan is suppressing the actual numbers to make themselves look better. There are the ones who will tell you that Japan is exaggerating the actual numbers to frighten people into getting vaccinated so that they can be tracked through microscopic microchips.

A friend recommended this great youtube video, too.
https://youtu.be/5r0AA41dgLU

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Z6IIAB
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Re: Another Study about Mask Effectiveness

Post by Z6IIAB » Mon Dec 13, 2021 7:10 am

Tanagra wrote:
Sun Dec 12, 2021 9:36 pm
I thought Japan was wary of vaccination themselves, but they mask up whenever possible. Did something change regarding the vaccines?
I did find an article from just about a year ago all about that, actually. https://www.japantimes.co.jp/news/2020/ ... ronavirus/

I can tell you 100% what changed regarding the vaccines. The truth. We in Japan got to watch, because in this modern reality information is available very quickly. We got to watch the surges in hospitalizations and deaths in other countries that occurred immediately after people stopped wearing masks, after lockdowns were lifted, and we also got to watch how these hospitalizations and deaths went down amongst vaccinated.

Here in Japan, since we started with the at-risk groups, the same drop in hospitalizations and death told us it was working. Now, general vaccinations began in July. I got my first shot on July 15th. My second August 19th. I'm one of the lucky ones who had no trouble at all. The numbers of people hospitalized and dying dropped like a stone as vaccinations increased. Tokyo, being one of the most populated cities, has always been our litmus test. Depending on which hoaxer you ask, there are the ones who will tell you that Japan is suppressing the actual numbers to make themselves look better. There are the ones who will tell you that Japan is exaggerating the actual numbers to frighten people into getting vaccinated so that they can be tracked through microscopic microchips.

A friend recommended this great youtube video, too.
https://youtu.be/5r0AA41dgLU
So great to see everyday solid evidence that vaccines save lives, like we always knew. Must make the antivaxxers so mad, but I do admire their creativity to mental-gymnastic themselves out of listening to reason.
Call me Celina. This forum still have a long way to go until it gets filled with its intended public. And I'll do my best to help us reach that goal. I'm a battleaxe, and when you hear my voice it'll be as loud as a thunder and as clear as a blue sky.

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RikkiTikkiTavi
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Re: Another Study about Mask Effectiveness

Post by RikkiTikkiTavi » Mon Dec 13, 2021 4:34 pm

Tanagra wrote:
Sun Dec 12, 2021 9:36 pm
A friend recommended this great youtube video, too.
https://youtu.be/5r0AA41dgLU
Thanks for that link. My first time watching Dr. John Campbell. He is a great presenter of information - and he has his two textbooks - Cambell's Physiology Notes and Cambell's Pathophysiology Notes available for download - for FREE.

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