from: https://www.politico.com/news/2020/03/30/maryland-shelter-in...
People are still going out and doing things around and with other people. And they shouldn't be, even with a mask.
And also, lots of doctors and nurses are coming down with Covid-19 right now despite being careful about their use of PPE.
EDIT: When people first started talking about surgical masks versus N95 respirators one study that came up was this one[1] from Ontario which showed that a bit over 20% of nurses using either of them got infected with influenza over the course of a flu season. Infections happen unless extreme care is taken as with things like Ebola.
[1] https://jamanetwork.com/journals/jama/fullarticle/184819
Presumably, these doctors didn't die during last year's flu epidemic. Nor during the previous years or decades of their practice. So something is different this year. Something they normally do to protect themselves, that isn't working this year.
Hm, they use hand washing, gowns, gloves, masks. Which one, do you think?