There are new questions about how long someone who’s recovered from COVID-19 is immune from getting the virus again. Second cases had been reported, and now a new study out of Hong Kong documents a reinfection at four-and-a half months.…

Since scientists aren’t sure whether people who have recovered from COVID-19 are immune to getting sick with it again, Dr. Theresa Tam says we’ll need to adjust our work and social lives to a world where the virus circulates but…