Realization of humoral immunity against SARS-CoV-2 infections

Formation of anti-infectious and post-vaccination anti-SARS-CoV-2 humoral immunity in medical workers of the perinatal center

In the context of the global spread of the new coronavirus infection, studies aimed at investigating formation of anti-infectious and post-vaccination immunity are of special importance, which is necessary to prevent and reduce morbidity and mortality due to SARS-CoV-2 infection. Purpose: to assess anti-infectious immunity against SARS-CoV-2 in various forms of the disease and development of post-vaccination humoral reactions in medical workers of the perinatal center. Materials and methods. A study of blood serum was carried out to assess SARS-CoV-2-specific IgM and IgG antibodies in 119 medical workers recovered after COVID-19, divided into groups based on the disease severity (mild, moderate and asymptomatic), as well as in 62 vaccinated employees, divided into groups according to age. Semi-quantitative measurement of virus-specific antibodies was carried out by ELISA with test systems SARS-CoV-2-IgG-ELISA-BEST and SARS-CoV-2-IgM-ELISA-BEST. Statistical processing of the research results was carried out using Microsoft Excel 2010 and Statistica 6. Quantitative characteristics were presented as median (ME), lower and upper quartiles (LQ1-UQ3); qualitative parameters as absolute value and relative number (%). Difference between groups was analyzed by using the 2 test (qualitative) and the MannWhitney U-test (quantitative). Results. The results of the study showed that the majority of employees with a moderate-severe form of SARS-CoV-2 had a high level of IgG (PR a positivity rate of more than 9.0 arbitrary units) 9 months after the disease compared to those who suffered from mild or asymptomatic (83.3% versus 25.8% and 13.3%, p 0.017) infection. The duration of IgG circulation after former illness had no relation to its severity and patient age. The effectiveness of the primary vaccination Sputnik V and revaccination with Sputnik Light and KoviVak was 100% after inoculating the vaccine second component. The lowest level of antibodies after the first vaccination is recorded in persons over 60 years old (1.48 (1.123.25 versus PR = 8.48(5.7810.11) and 9.27 (5.8410.31) arbitrary units, p 0.017)), in comparison with young and middle-age subjects. The speed SARS-CoV-2 elimination of IgG at 6, 9 or more months after vaccination depends on relevant initial peak antibody concentration. Subjects who were initially vaccinated with the KoviVac vaccine, IgG was not detected 2 months after vaccination. The protective effect of Sputnik V, Sputnik Light, KoviVac after re-infection with SARS-CoV-2 averages 71.2%. Conclusion. Thus, the results obtained on assessing anti-infectious and post-vaccination immunity against SARS-CoV-2 emphasize the need for further studies on a larger patient cohort, especially in those with asymptomatic infection as well as the elderly subjects.