HONESTLY, THIS NUMBER SEEMS LOW TO ME. One in five with COVID-19 passes it to others in household, data shows. At least, lower than I expected. But a nephew who was pretty sick with Covid for a couple of weeks never did infect my sister or brother-in-law. He did isolate himself in his room, which is an addition with separate HVAC, and I sent them one of these HEPA/UV air filters, but still. And a high school friend whose family caught it in NYC in early March never did get it; 3 out of 6 in her family were sick and the others just never came down with it despite being in constant proximity.

Plus: “Households are favorable environments for transmission.” Interestingly, our whole strategy seems to have involved keeping people in their households as much as possible.