…“Last fall, there were reports that antibodies wane quickly after infection with the virus that causes COVID-19, and mainstream media interpreted that to mean that immunity was not long-lived,” says senior author Ali Ellebedy, PhD, an associate professor of pathology and immunology, medicine, and molecular microbiology, in a university release.
“But that’s a misinterpretation of the data. It’s normal for antibody levels to go down after acute infection, but they don’t go down to zero; they plateau. Here, we found antibody-producing cells in people 11 months after first symptoms. These cells will live and produce antibodies for the rest of people’s lives. That’s strong evidence for long-lasting immunity.”
…The results reveal COVID antibodies in the blood dropped off quickly within a few months of clearing the virus. However, these antibodies did not disappear entirely, they leveled off and scientists still detected them in patients 11 months later.
Moreover, 15 of the bone marrow samples from coronavirus patients contained antibody-producing cells which target COVID-19. The bone marrow from the five patients who came back to give a second sample still had these cells present four months later. On the other hand, all 11 people who did not get COVID-19 did not have any of these antibody-producing cells in their bone marrow.
For COVID patients, researchers say there’s no reason to think these cells will ever leave the human body.
“People with mild cases of COVID-19 clear the virus from their bodies two to three weeks after infection, so there would be no virus driving an active immune response seven or 11 months after infection,” Ellebedy explains. “These cells are not dividing. They are quiescent, just sitting in the bone marrow and secreting antibodies. They have been doing that ever since the infection resolved, and they will continue doing that indefinitely.”
