Immunity to coronavirus infection can last at least six months, this was confirmed by a study published in Nature and made with 87 people who were infected with the virus.
The study reveals that levels of specific memory B cells (whose mission is to defend the organism from future aggressions of the same pathogen by generating antibodies) were kept constant during the study period.
The results suggest that people who were previously infected with the coronavirus may generate a quick and effective response to the virus if they are exposed again.
The human immune system responds to infection by producing antibodies that can specifically neutralize the infectious agent. It was shown that human antibodies against covid-19 protect against infection in animal models.
The levels of these antibodies may decrease over time, but memory B cells, as the name suggests, they are reminiscent of the infectious agent. Thus, they can prompt the immune system to produce the same antibodies when reinfected.
Michel Nussenzweig and his colleagues at Rockefeller University in New York evaluated 87 people with a confirmed diagnosis of covid-19 a 1.3 and 6.2 months later of infection. They found that although the activity of the neutralizing antibodies declines over time, the number of memory B cells remains unchanged.
Furthermore, the authors noted that the antibodies produced by these cells are more potent than the original antibodies. Therefore, they can be more resistant to mutations in the virus protein that allows the entry of the cell.
These observations demonstrate that memory B cells have the ability to evolve in the presence of small amounts of persistent viral antigen (small virus proteins that can be detected by the immune system).
The continued presence and evolution of memory B cells suggests that people may be able to rapidly produce potent neutralizing antibodies and have some immunity upon reinfection with the coronavirus, the authors conclude.