Researchers from the Howard Hughes Medical Institute in the United States found that after recovering from COVID-19, a person develops persistent and powerful immunity against mutated strains of coronavirus within six months. This means that cured people are unlikely to get sick again after at least six months. This is reported in the preprint of the article, uploaded to the bioRxiv.org repository.
The researchers analyzed blood samples from 149 patients for the presence of immune cells that produce neutralizing antibodies that target SARS-CoV-2. All volunteers had antibodies to coronavirus a month after recovery. According to the researchers, a vaccine that promotes the synthesis of such antibodies should be effective in providing protection to the general population.
Although the concentration of antibodies targeting the receptor-binding domain (RBD) in the S-protein of the coronavirus decreases over time, as does the neutralizing activity in blood plasma, the number of B cells does not change. Six months later, the antibodies they produce have increased activity and resistance to mutations in RBD, which indicates the ongoing evolution of the humoral immune response.
The humoral immune response of the body is antibodies against pathogens found in blood and lymph fluids, as well as in blood serum.