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comment by am_Unition
am_Unition  ·  931 days ago  ·  link  ·    ·  parent  ·  post: Are We Wearing the Wrong Masks?

Yeah, a pretty terrible interval of time to conduct this study in Bangladesh. From Nov. 2020 to April 2021, only about the last third of that interval (mid-March to May 1st) might give you some good statistics. I understand choosing Bangladesh because of how relatively inexpensive it is to pay people there, but there aren't many large countries with lower per capita infections, to date, and most of Bangladesh's cases are more recent than the study's time frame. Of course, Bangladesh is also assuredly not testing as much per capita, so this all just sucks. To me, the study says "Hey, our error bars are small enough to be on the same order of magnitude as the measurement for only one deduction we were trying to make".

Muh physics says that a decent cloth mask should at least somewhat hinder the propagation of aerosols. I hated agreeing with Bill Nye (because he's notoriously a dick off camera), but it really is about as simple as holding out a candle in front of your masked face and trying to blow it out. Candle stays lit? Good. If you're emitting covid, it's got a better chance of falling closer to the floor instead of reaching someone else's face than if you were maskless. If covid is already in the air near your face, though, surely a cloth mask will do little, if anything, to filter it out.

Accusing pro-maskers of virtue signaling isn't completely without merit, but at this point, masking is pretty much also vaccine signaling in the US. Ironically, the people masking up are probably more likely to also be vaccinated.

edit:

    ... a big delta to work with

Careful ;). Not as bad as "Delta Air Lines", though.





wasoxygen  ·  931 days ago  ·  link  ·  

Marginal Revolution described a sneering critique of "one of the worst studies i've ever seen in any field" as "Overstated, unreasonable, and too polemic" and your sober expression of reservations is a lot easier on the eyes.

But polemic does not mean wrong, and the author makes some valid points:

· Medpage Today observes that "The primary endpoint was reporting symptoms consistent with COVID-19 followed by a positive serology test to document SARS-CoV-2 infection." But this measure (aside from the unreliability of self-reported symptoms, and more than half the people with symptoms refusing the blood test) was not taken at the beginning of the study, so the before-and-after situation is open to interpretation.

· When the study was mentioned in the Washington Post, it pointed out that "the intervention group was found to practice more social distancing, which may complicate the findings on masks." There were many other consequences of the interventions, but masks were given primary credit, with the usual hyperbolic headline stating "Massive randomized study is proof that surgical masks limit coronavirus spread".

    I understand choosing Bangladesh because of how relatively inexpensive it is to pay people there

"Randomization of treated villages to no incentive, monetary incentive of 190 USD, or nonmonetary incentive. We announced that the monetary reward or the certificate would be awarded if village-level mask wearing among adults exceeded 75% 8-weeks after the intervention started."

So some villages had something to lose if they didn't please the researchers.

Has the spread of influenza-like illness changed so much since 2019 that we can't rely on the WHO's review of the evidence?