Why are coronavirus reinfections happening?

Most people who recover from COVID-19 have some protection against the new coronavirus, SARS-CoV-2, that causes this disease due to antibodies and other immune responses, Report states, citing BMJ Case Reports.

Some research suggests this protection lasts for at least eight months.

But reinfections are possible, even just a few months apart, a group of physicians from Yale University School of Medicine warned today in BMJ Case Reports.

They reported on a man in his 40s who had a severe case of COVID-19 last April and a mild case 4 months later.
In April and August, he tested positive for SARS-CoV-2. In between, he had four negative tests.

It isn’t the first case of someone contracting the new coronavirus a second time.

However, it’s difficult to know how common reinfections are because scientists don’t routinely monitor for them, and symptoms may be less noticeable the second time around.

“A lot of reinfections are very mild. People don’t even realize they have gotten reinfected,” said Theodora Hatziioannou, Ph.D., a virologist at Rockefeller University. “So, I would guess that [reinfection] happens a lot.”