“It tells me that even if you got infected, it doesn’t mean that you have a super immune response,” Dr. Ellebedy said. The findings reinforce the idea that people who have recovered from Covid-19 should be vaccinated, he said.
Five of the participants in Dr. Ellebedy’s study donated bone marrow samples seven or eight months after they were initially infected and again four months later. He and his colleagues found that the number of memory B cells remained stable over that time.
Dr. Nussenzweig’s team looked at how memory B cells mature over time. The researchers analyzed blood from 63 people who had recovered from Covid-19 about a year earlier. The vast majority of the participants had mild symptoms, and 26 had also received at least one dose of either the Moderna or the Pfizer-BioNTech vaccine.
As memory B cells continued to evolve, the antibodies they produced developed the ability to neutralize an even broader group of variants. This ongoing maturation may result from a small piece of the virus that is sequestered by the immune system — for target practice, so to speak.
A year after infection, neutralizing activity in the participants who had not been vaccinated was lower against all forms of the virus, with the greatest loss seen against the variant first identified in South Africa.
Vaccination significantly amplified antibody levels, confirming results from other studies; the shots also ramped up the body’s neutralizing ability by about 50-fold.
Senator Rand Paul, Republican of Kentucky, said on Sunday that he would not get a coronavirus vaccine because he had been infected in March of last year and was therefore immune.
But there is no guarantee that such immunity will be powerful enough to protect him for years, particularly given the emergence of variants of the coronavirus that can partially sidestep the body’s defenses.
The results of Dr. Nussenzweig’s study suggest that people who have recovered from Covid-19 and who have later been vaccinated will continue to have extremely high levels of protection against emerging variants, even without receiving a vaccine booster down the line.
“It kind of looks exactly like what we would hope a good memory B cell response would look like,” said Marion Pepper, an immunologist at the University of Washington in Seattle who was not involved in the new research.
This content was originally published here.