Got a Covid Booster? You Probably Won’t Need Another for a Long Time

Last year, researchers showed that an elite school inside the lymph nodes where B cells train, called the germinal center, remains active for at least 15 weeks after a second dose of the Covid vaccine. In an updated study published in the journal Nature the same team showed that six months after vaccination, memory B cells continue to mature, and the antibodies they produce acquire the ability to recognize new variants.

“These antibodies six months later are better binders and more powerful neutralizers than those produced a month after immunization,” said Ali Ellebedi, an immunologist at Washington University in St. Louis, who led the study.

In the latest study, another team showed that the third injection creates an even richer pool of B cells than the second injection, and the antibodies they produce recognize a wider range of variants. In laboratory experiments, these antibodies were able to reflect beta, delta, and omicron variants. In fact, more than half of the antibodies detected one month after the third dose were able to neutralize Omicron, although no vaccine was developed for this variant, the study found.

“If you get the third dose, you will have a fast response that will have some specificity for Omicron, which explains why people who get the third dose feel much better,” said Michel Nussenzweig. , an immunologist at Rockefeller University who led the study.

Memory cells obtained after infection with the coronavirus, rather than vaccines, appear to be less effective against the Omicron variant. according to research published last month in the journal Nature Medicine. The immunity generated by the infection “is quite variable, while the response to the vaccine is much more consistently good,” said Markus Buggert, an immunologist at the Karolinska Institute in Sweden, who led the study.

While most people, vaccinated or not, show only a slight decrease in T-cell response to Omicron, about one in five had a “significant decrease in response” of about 60 percent, according to Dr. Baggert. The differences are most likely due to their underlying genetic makeup, he said.

However, recent studies show that most people have long-term immunity from infection or vaccination. Even if mutations in the new variants change some of the viral regions that T cells recognize, there will still be enough others to support a strong enough immune response, experts say.

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