Dr. Bhattacharya noted that most of what scientists know about the persistence of germinal centers is based on animal research. The new study is the first to show what happens in people after vaccination.
The results suggest that a vast majority of vaccinated people will be protected over the long term at least, against the existing coronavirus variants. But older adults, people with weak immune systems and those who take drugs that suppress immunity may need boosters; people who survived Covid-19 and were later immunized may never need them at all.
Exactly how long the protection from mRNA vaccines will last is hard to predict. In the absence of variants that sidestep immunity, in theory immunity could last a lifetime, experts said. But the virus is clearly evolving.
Anything that would actually require a booster would be variant-based, not based on waning of immunity, Dr. Bhattacharya said. I just dont see that happening.
People who were infected with the coronavirus and then immunized see a major boost in their antibody levels, most likely because their memory B cells which produce antibodies had many months to evolve before vaccination.
The good news: A booster vaccine will probably have the same effect as prior infection in immunized people, Dr. Ellebedy said. If you give them another chance to engage, they will have a massive response, he said, referring to memory B cells.
In terms of bolstering the immune system, vaccination is probably better than recovering from the actual infection, he said. Other studies have suggested that the repertoire of memory B cells produced after vaccination is more diverse than that generated by infection, suggesting that the vaccines will protect better against variants than natural immunity alone.
Immune cells are still organizing to fight the coronavirus months after inoculation, scientists reported.
