Аnalysis of the duration and intensity of the humoral immune response in medical workers after COVID-19

The article presents data on the duration and intensity of the humoral immune response in medical workers who had COVID-19 in the first wave of the pandemic. The response was analyzed based on the production of immunoglobulin M (IgM) and G (IgG) antibodies to SARS-CoV-2. Using ELISA immunoassay systems manufactured by «Vector-Best» (Novosibirsk, RF) and foreign test systems based on immunofluorescence analysis by Abbott (USA), a comparative assessment of the production of antibodies to SARS-CoV-2 was carried out. The presented semi-quantitative and quantitative data on IgM and IgG antibodies to SARS-CoV-2 in dynamics for the period from May 2020 to May 2021 in medical workers who had had COVID-19. The difference in the antibodies’ detection and the dynamics of their decrease depending on the type of antibodies detected are shown. Data on the frequency of occurrence of IgM antibodies to SARS-CoV-2 in medical workers who had had COVID-19 during the observed period are presented, with the assumption of reinfection or persistence of the virus. Data are presented on the number of IgG antibodies expressed in international units (BAU/ml) and the relative number of patients who managed to maintain different (150/300/590 BAU/ml) protective levels of antibodies to SARS-CoV-2 over the observed period, including those with a minimum level of protection by the minimum titer of neutralizing antibodies.