Immunity to Covid-19 among those who have previously been infected with the virus appears to be “very” long-lasting, an analysis published Monday in the leading medical journal Nature found, bolstering other recent research that suggests protection from prior infection and vaccination could last years—or even decades.
The analysis by a group of top scientists from labs across the country looked at dozens of people who were infected with the coronavirus about a year ago.
As is typical, these individuals saw a severe drop-off in their antibody concentrations after they were initially infected with Covid-19.
But a look at their bone marrow both seven and 11 months later found the presence of so-called memory B cells, which can retain the memory of a virus and release antibodies when needed.
Memory B cells can be maintained in the bone marrow for “decades, if not a lifetime,” the analysis notes, and the numbers found in recovered Covid-19 patients match those identified in people vaccinated against tetanus or diphtheria, vaccines that both provide “long-term immunity” to the diseases they combat.
Vaccination helps boost immunity among the previously infected even further, the research found, and appears to adequately protect against Covid-19 variants.
“The data suggests that immunity in convalescent individuals will be very long lasting and that convalescent individuals who receive available mRNA vaccines will produce antibodies and memory B cells that should be protective against circulating SARS-CoV-2 variants,” the analysis concluded.
The Nature analysis is the latest in a slew of research indicating immunity to Covid-19 could last longer than previously expected. A separate study published in Nature last month, along with research published on server BioRxiv, both came to similar conclusions, with the latter finding memory B cells continue to mature and strengthen for at least a year after initial infection. However, these studies—and other experts—have highlighted that the response appears to be different among those who haven’t had the virus before, and these people will likely need booster shots. Meanwhile, a study published last month in the Lancet medical journal underscored the importance of vaccines as it found past coronavirus infections don’t confer strong enough immunity to fully protect against reinfection, posing a high risk for unvaccinated older people.
WHAT TO WATCH FOR
The evolving understanding of Covid-19 immunity is critical to public health officials and drugmakers as they hash out the future of vaccinations. Pfizer-BioNTech and Moderna have both suggested booster shots could be necessary as soon as September to re-top immunity levels. However, the U.S.’ leading government agencies have so far held off on concrete recommendations for when—or how often—these could be necessary.
“Immunity to the Coronavirus May Persist for Years, Scientists Find” (The New York Times)