This is an in vitro study. In vivo, there's a self-selection bias for non-occupational N95 use that would tilt observed difference in protection rates between N

This is an in vitro study. In vivo, there's a self-selection bias for non-occupational N95 use that would tilt observed difference in protection rates between N95 and surgical mask wearers. Original study [0] MPG press release [1] [0] https://www.pnas.org/content/pnas/118/49/e2110117118.full.pdf https://www.pnas.org/content/pnas/118/49/e2110117118.full.pd... [1] https://www.mpg.de/17916867/coronavirus-masks-risk-protection https://www.mpg.de/17916867/coronavirus-masks-risk-protectio...