Large Danish RCT N-4900 of masking for prevention of C19 infection FAILED, rather predictably (given influenza RCTs) with a non-significant & clinically IRRELEVANT “0.3%” absolute “risk reduction”. Published in preeminent internal medicine Ann Intern Med https://t.co/u740usABFH pic.twitter.com/FDYDdWapC0

— Andrew Bostom (@andrewbostom) November 18, 2020