Around the world, nursing homes and assisted living facilities have been a hotbed for Covid-19 outbreaks. Because older people are particularly vulnerable, the facilities have had some of the deadliest outcomes during the pandemic. But some nursing homes have done much better than others at containing the virus. Angelica LaVito reports on a Seattle-area assisted living company that learned the lessons of the pandemic early, and has managed to keep outbreaks from raging out of control.