Can You Get Coronavirus More Than Once?

Recovered patients who test positive again raise questions about the virus’s ability to reactivate

Over 100 people in South Korea who were considered to be cleared of Covid-19 have tested positive again. It isn’t clear why this is happening, but the unsettling discovery has prompted the World Health Organization (WHO) to begin an official investigation.

Several explanations for the positive test results have been proposed in the meantime, including the possibility that the…