Although reinfections with SARS-CoV-2 are rare, and often asymptomatic or mild, they can be severe.
In another analysis, the researchers compared more than 14,000 people who had a confirmed SARS-CoV-2 infection and were still unvaccinated with an equivalent number of previously infected people who subsequently received one dose of the Pfizer-BioNTech vaccine. (In Israel, it’s recommended that people who have been previously infected get just one dose.) The team found that the unvaccinated group was twice as likely to be reinfected as the singly vaccinated.
“We continue to underestimate the importance of natural infection immunity … especially when [infection] is recent,” says Eric Topol, a physician-scientist at Scripps Research. “And when you bolster that with one dose of vaccine, you take it to levels you can’t possibly match with any vaccine in the world right now.”