Mild COVID Induces Antibodies That Can Last Lifetime: Study

In a recent study published in the journal Nature, it was found that those who had mild cases of coronavirus could have antibody protection that could last a lifetime.

The researchers from Washington University School of Medicine in St. Louispeople, found that months after recovering from mild COVID, people had long-lived plasma cells in their bone marrow, which were secreting antibodies against SARS-CoV-2, the virus that causes the disease.

It was also found that repeated bouts of illness are likely to be uncommon.

When there is a viral infection, antibody-producing immune cells rapidly multiply and circulate in the blood. Once the infection is resolved, the immune cells die and the antibody levels in the blood drop.

However, a small population of antibody-producing cells, called long-lived plasma cells, migrate to the bone marrow and settle in, the researchers said.

In the study, the researchers analysed blood from 77 people at three-month intervals, starting about a month after their infection with the coronavirus. Most participants had had mild cases of COVID, while only six had been hospitalised.

The researchers found that the antibody levels of the COVID participants dropped rapidly in the first few months after infection and then mostly levelled off, with some antibodies detectable even 11 months after infection.

The team obtained bone marrow samples from 19 people around seven months after they had been infected and found that 15 samples contained antibody-producing cells specifically targeting the virus that causes COVID.

Even after four months, such cells could be found in the five people who came back to provide a second bone-marrow sample.

According to the researchers, none of the 11 people who had never had COVID had such antibody-producing cells in their bone marrow.

The study indicates that mild COVID infection elicits a long-lived bone marrow plasma cell response.