COVID-19 reinfections have seemingly become common since omicron and its sublineages took hold, The New York Times reported June 11.
In today's COVID-19 landscape, it's no longer peculiar to hear of someone who has been infected two or three times. Pre-omicron, however, reinfections weren't commonplace.
A team of scientists at Weill Cornell Medicine in Qatar estimated that infection with delta or an earlier virus strain was 90 percent effective at preventing reinfection in both vaccinated and unvaccinated people.
"But omicron really changed that calculus," Laith Abu-Raddad, PhD, an infectious disease epidemiologist who led the research, told the Times. After omicron's emergence, prior infections provided just 50 percent protection against subsequent infections. Research has also suggested people who are older or immunocompromised are more vulnerable to reinfection, since they make too few or poor-quality antibodies.
The good news, however, is that none of the more than 1,300 reinfections Dr. Abu-Raddad and team have tracked from the start of the pandemic through May 2021 have led to hospitalization in an intensive care unit or death.
Experts have echoed the message that the primary purpose of vaccines at this point in the pandemic is to prevent severe illness and that the virus is evolving to behave more like its relative viruses that cause common colds.
"I've thought, almost since the beginning of this pandemic, that COVID-19 is eventually going to become an inevitable infection that everybody gets multiple times, because that's just how a new respiratory virus gets established in the human population," Amesh Adalja, MD, an infectious disease specialist at Baltimore-based Johns Hopkins University, told the Times.