The study included data from 2,112 patients from Moscow, the Moscow region, Ryazan, Nizhnevartovsk and Kursk. Scientists identified two groups of participants: some were tested for antibodies after suffering COVID-19 or suspicion of it, others were examined as part of professional examinations, for example, employees of pharmaceutical and medical companies.
Scientists have found a large difference between these groups depending on the region: for example, in Moscow, antibodies were detected in 17% of those who applied independently and in 7.5% of company employees, while in the Moscow region these indicators were 39% and 9.3%, respectively. … In Nizhnevartovsk, the number of those who had recovered was significantly lower: 14% and 3%. The average rate of those who had recovered from COVID-19 during the spring wave according to the results of the study was 11%
During the study, DNCOM specialists also monitored the dynamics of antibody production in the blood of volunteers and found that they can appear at very late stages. According to Andrey Isaev, there were patients in whom antibodies were produced only after 14 days, and even after 44 days, in some volunteers the maximum concentration of antibodies was reached by 74 days. By the sixth month, titers decreased in all study participants to the level of the control group.
“The most striking finding was that the antibody titer dropped faster in those who were seriously ill than in those who had more COVID-19. Moreover, the average concentration of antibodies in these patients was significantly lower. So the hypothesis that if you are seriously ill, then you will get the maximum amount of antibodies, has not been confirmed, at least within the framework of our study, ”said Andrey Isaev.
According to the expert, there is a simple explanation for this phenomenon: most patients with a severe course have concomitant diseases that reduce the resources of the immune system.
Earlier, an international group of scientists reported that patients who have suffered a severe form of COVID-19 are more likely to develop antibodies. Scientists hypothesize that a higher viral load causes a strong inflammatory response, which stimulates the production of more antibodies.