Even a mild case of COVID-19 can create antibodies that could give you lifetime protection from the virus, according to a new study.
“Months after recovering from mild cases of COVID-19, people still have immune cells in their body pumping out antibodies against the virus that causes COVID-19, according to a study from researchers at Washington University School of Medicine in St. Louis,” StudyFinds reports. “Such cells could persist for a lifetime, churning out antibodies all the while.”
The study’s findings were published on Monday in the journal, Nature. The researchers said there is evidence that immunity triggered by COVID-19 infection will be “extraordinarily long-lasting.”
“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,” said senior author Ali Ellebedy, an associate professor of pathology and immunology. “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.”
Ellebedy said that after COVID-19 clears up, specialized immune cells called long-lived plasma cells move to the bone marrow, where they then manufacture low levels of COVID antibodies to help prevent reinfection with the virus.
Said the study: “Antibodies are proteins that can recognize and help to inactivate viral particles and are a key immune defense. After a new infection, short-lived cells called plasmablasts are an early source of antibodies. But these cells recede soon after a virus is cleared from the body, and other, longer-lasting cells make antibodies: memory B cells patrol the blood for reinfection, while bone marrow plasma cells (BMPCs) hide away within bones, trickling out antibodies for decades.”
“As expected, antibody levels in the blood of the COVID-19 participants dropped quickly in the first few months after infection and then mostly leveled off, with some antibodies detectable even 11 months after infection,” Washington University said. “Further, 15 of the 19 bone marrow samples from people who had had COVID-19 contained antibody-producing cells specifically targeting the virus that causes COVID-19. Such cells could still be found four months later in the five people who came back to provide a second bone-marrow sample. None of the 11 people who had never had COVID-19 had such antibody-producing cells in their bone marrow.”
“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 said. “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.”