One thing to understand abt masks is viral dose: Evidence suggests it takes a big dose of the Coronavirus to cause an infection. Masks can be effective even if they don’t block 100% of pathogens, bc they can still lower your viral dose and protect you https://elemental.medium.com/the-science-and-politics-of-masks-in-the-covid-19-pandemic-8d5a63f6a20c?source=post_page-----8d5a63f6a20c----------------------

This is kind of a gross analogy explaining why we all need to wear masks, but I guess it makes sense — from UCSF Chair of Medicine @Bob_Wachter

What if Americans were obsessing over the wrong thing — wiping down their mail etc — while ignoring masks, the first line of defense for any respiratory diseases?
https://twitter.com/bob_wachter/status/1264028001710170112?s=21 https://twitter.com/bob_wachter/status/1264028001710170112