Another crucial study showing how dangerous indoor situations can be. An alarming 94 (out of 216) people on the same floor in a call center in Korea got infected—an attack rate of 43.5%! But look at the schema. Most infections are on one side of the room. https://wwwnc.cdc.gov/eid/article/26/8/20-1274_article

Also only three people on other floors infected despite "frequent contact in the lobby or elevators" (but not a lot of travel between floors and no shared restaurant). Much lower transmission also later to household members (16.2% attack rate). High risk for crowded indoors+time.

Since people are looking at these studies today, I'm going put this paper here again (I'm a co-author). These studies increase the potential value of universal masking—especially indoors. https://twitter.com/zeynep/status/1249805628240953346

Also this article: https://twitter.com/zeynep/status/1253030146262605825