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

Abstract

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 χ2 test (qualitative) and the Mann-Whitney 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 (1.12-3.25 versus PR = 8.48 (5.78-10.11) and 9.27 (5.84-10, 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.