Good news on immunity
Scientists have feared that immunity to the coronavirus, whether through infection or vaccination, may be short-lived. But a pair of novel studies suggest that immunity lasts for at least a year — and maybe even decades for some people.
“For people who have had Covid and have been vaccinated, this is excellent news because it means that they will probably never need a booster again — it seems like they’re pretty much set for life,” said my colleague Apoorva Mandavilli, who covers science for The Times. “For people who haven’t had Covid but are vaccinated, those people will probably need boosters, and within a year or so.”
Both of the studies looked at a type of immune cell that can remember the virus and lives in the bone marrow until it is needed to produce antibodies.
“Getting bone marrow is an involved procedure, it’s not just like drawing blood,” Apoorva said. “So the fact that they were able to get bone marrow from people, and not just once but multiple times, is a big deal.”
The scientists discovered that as these immune cells continued to evolve, the antibodies they produced became better at fighting infection.
“Even after the active infection was over, these cells kept learning because the immune system retained a piece of the virus,” Apoorva said. “Over time, the immune cells continued to improve how well they could target the virus. They became broader in their repertoire, so they could work against a much broader range of variants.”
Vaccines may not offer the same results, because immune memory is likely organized differently after immunization, than with an infection. And even those who have recovered from an infection still need doses.
“Some subset of people don’t necessarily produce a very strong immune response when they’ve been exposed to the virus,” Apoorva said. “So, really, everybody should get vaccinated, whether they’ve been infected or not.”