New variants raise worry about COVID-19 virus reinfections

Evidence is mounting that having COVID-19 may not protect against getting infected again with some of the new variants. People also can get second infections with earlier versions of the coronavirus if they mounted a weak defense the first time, new research suggests.

How long immunity lasts from natural infection is one of the big questions in the pandemic. Scientists still think reinfections are fairly rare and usually less serious than initial ones, but recent developments around the world have raised concerns.