A 33-year-old man was infected a second time with the coronavirus more than four months after his first bout, the first documented case of so-called reinfection, researchers in Hong Kong reported Monday.
The finding was not unexpected, especially given the millions of people who have been infected worldwide, experts said. And the man had no symptoms the second time, suggesting that even though the prior exposure did not prevent the reinfection, his immune system kept the virus somewhat in check.
"The second infection was completely asymptomatic — his immune response prevented the disease from getting worse,” said Akiko Iwasaki, an immunologist at Yale University who was not involved with the work but reviewed the report at The New York Times’ request. "It’s kind of a textbook example of how immunity should work.”