The body of COVID-19 survivors is able to resist re-infection even with a decrease in the number or complete absence of antibodies. This was stated by a group of scientists from Switzerland and the United States following a study, the results of which are reported by the journal Nature. The publication notes that at the time of publication, the authors' conclusions were not edited.
Examination of 87 people who had recovered from the infection after 1.3 and 6.2 months confirmed a significant decrease in the titers of IgM and IgG antibodies, the amount of IgA decreased insignificantly. Plasma neutralizing activity decreased fivefold. However, this retains a certain number of specific memory B cells that recognize the virus. If it reappears in the body, these cells re-start the expression of antibodies.
The study also showed a rather unexpected result - the renewed antibodies have increased activity and resistance to SARS-CoV2 mutations. According to scientists, this fact indicates the ongoing evolution of the body's humoral immune response to the new coronavirus.
“We came to the conclusion that the response of memory B cells to SARS-CoV-2 develops in the period from one and a half to six months after infection, which is consistent with the currently known periods of preservation of the biological activity of antibodies,” the authors of the work reported.
Recall, according to the results of several studies, antibodies neutralizing the virus persist, on average, for five months. Scientists believe that the longest lasting immunity is formed in patients with severe COVID-19.
