Reason that past clinical studies, focusing on health-care worker outcomes, are not the best indicator is that masks for *source-control* is not an individual level variable. It's like asking if filters on car exhausts lower air pollution by measuring the air ... inside each car.
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Will do. I'm catching up on the recent papers myself! Proper natural experiments will be the best level of evidence we have. There was talk early on doing randomized studies but people couldn't figure out any way to do it ethically or quickly.
End of conversation
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