No placebo to compare to, but it sure looks like masks worked - Printable Version
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+--- Thread: No placebo to compare to, but it sure looks like masks worked (/thread-20097.html)
No placebo to compare to, but it sure looks like masks worked - BostonCard - 07-16-2020
Remember the two hairstylists in Missouri who were found to have been infected with COVID-19. Well, they did not infect any of their 139 clients, which is either exceedingly fortunate, or very strong evidence that you can safely open things up provided that people wear masks.
https://www.cdc.gov/mmwr/volumes/69/wr/mm6928e2.htm?s_cid=mm6928e2_w
Quote:Summary
What is already known about this topic?
Consistent and correct use of cloth face coverings is recommended to reduce the spread of SARS-CoV-2.
What is added by this report?
Among 139 clients exposed to two symptomatic hair stylists with confirmed COVID-19 while both the stylists and the clients wore face masks, no symptomatic secondary cases were reported; among 67 clients tested for SARS-CoV-2, all test results were negative. Adherence to the community’s and company’s face-covering policy likely mitigated spread of SARS-CoV-2.
What are the implications for public health practice?
As stay-at-home orders are lifted, professional and social interactions in the community will present more opportunities for spread of SARS-CoV-2. Broader implementation of face covering policies could mitigate the spread of infection in the general population.
BC
RE: No placebo to compare to, but it sure looks like masks worked - magnus - 07-16-2020
(07-16-2020, 10:37 PM)BostonCard Wrote: Remember the two hairstylists in Missouri who were found to have been infected with COVID-19. Well, they did not infect any of their 139 clients, which is either exceedingly fortunate, or very strong evidence that you can safely open things up provided that people wear masks.
https://www.cdc.gov/mmwr/volumes/69/wr/mm6928e2.htm?s_cid=mm6928e2_w
Quote:Summary
What is already known about this topic?
Consistent and correct use of cloth face coverings is recommended to reduce the spread of SARS-CoV-2.
What is added by this report?
Among 139 clients exposed to two symptomatic hair stylists with confirmed COVID-19 while both the stylists and the clients wore face masks, no symptomatic secondary cases were reported; among 67 clients tested for SARS-CoV-2, all test results were negative. Adherence to the community’s and company’s face-covering policy likely mitigated spread of SARS-CoV-2.
What are the implications for public health practice?
As stay-at-home orders are lifted, professional and social interactions in the community will present more opportunities for spread of SARS-CoV-2. Broader implementation of face covering policies could mitigate the spread of infection in the general population.
BC
There was/is a theory that most of the cases are cause by super spreaders. I guess, by that, they mean certain people are more prone to spread the disease than others. If that's the case, it might also be true that these two individuals just aren't high volume producers of the virus.
Not trying to throw water on this positive, but rather wondering if anything became of the super spreader theory? I sure do hope that masks, even cloth ones, help as much as the CDC is suggesting.
RE: No placebo to compare to, but it sure looks like masks worked - M T - 07-17-2020
(07-16-2020, 11:55 PM)magnus Wrote: There was/is a theory that most of the cases are cause by super spreaders. I guess, by that, they mean certain people are more prone to spread the disease than others. If that's the case, it might also be true that these two individuals just aren't high volume producers of the virus.
Not trying to throw water on this positive, but rather wondering if anything became of the super spreader theory? I sure do hope that masks, even cloth ones, help as much as the CDC is suggesting.
If you read the article, you would know that stylist A apparently infected stylist B, and 4 housemates (3 are family) of A also got the disease.
Two other contacts of stylist B got the disease (after spending time unmasked with A). No other stylists got the disease (not stated whether they spent time unmasked with A or B).
What I wonder about is why the Health Department only did contact tracing on the clients seen after the first symptoms of A and after the first symptoms of B, rather than going back in time a few days.
(The CDC hosts a number of articles it deems interesting. The CDC did not do the study or write it up. The report was (or will be) published elsewhere. It is the 'CDC's article' like it would be the 'library's "Moby Dick"')
RE: No placebo to compare to, but it sure looks like masks worked - burger - 07-17-2020
People, THIS IS AN N OF 2, not 160, and we should not make ANY policy decisions based on it. Maybe these two hairstylists were not shedding much virus. Maybe the ventilation in their shops was excellent. Maybe there was something else going on.
This doesn't even show that masks prevent the spread because we don't know what would've happened without a mask. Maybe the relatively short time needed for a haircut isn't long enough to spread the virus. Other studies have suggested that longer contact is necessary.
Also, they tested fewer than half the clients, so they can't rule out asymptomatic cases.
This is, at best, an interesting anecdote. But not a useful one.
RE: No placebo to compare to, but it sure looks like masks worked - BostonCard - 07-17-2020
Yes, this is why I note in the subject "No placebo to compare to, but...". No, this is not a rigorous study with dozens of hairstylists, some who wore masks and some who didn't.
That being said, when we first heard the story of the hairstylists, how many people thought "oh god, how many clients are they going to have infected?"
You wouldn't make policy on that basis, but you might feel a bit better getting a haircut with proper PPE and hygiene mechanisms.
BC
RE: No placebo to compare to, but it sure looks like masks worked - fullmetal - 07-17-2020
This is a data point in favor of masks, no matter how minor. What's the harm in advocating for policy action based on this data point? Is mask-wearing so harmful that this incident has to be ignored?
If you subscribe to the superspreader theory, then you should advocate for universal mask wearing since we don't know who's likely to be a superspreader...so everyone has to mask up.
If you don't subscribe to the superspreader theory, then you might say that this incident shows how effective masks are, and you should advocate wearing masks in all situations.
The only conclusion you should not draw from this incident is that masks are the solution, even in close quarters. That seems to be asking for trouble.
RE: No placebo to compare to, but it sure looks like masks worked - Hurlburt88 - 07-18-2020
good articles in the WSJ today, unfortunately behind a paywall. One lighthearted . . . humor has been shown to be very useful in nudging people on issues like this--NG had a blurb on this related to climate change science a while back. I do feel like the tide is inexorably turning to universal masking, just a matter of how much time and unneeded extra spread occurs during this slow process.
https://www.wsj.com/articles/face-masks-really-do-matter-the-scientific-evidence-is-growing-11595083298?mod=hp_lead_pos6
https://www.wsj.com/articles/please-wear-a-face-mask-so-i-can-shut-up-about-wearing-face-masks-11594991085
https://www.wsj.com/articles/mandatory-mask-laws-arent-enforced-as-coronavirus-continues-to-spread-11594978200