Acta Biomedica Scientifica (Nov 2020)

Studying Humoral Immune Response at Mild and Asymptomatic COVID-19 Forms

  • S. V. Balakhonov,
  • V. I. Dubrovina,
  • M. V. Chesnokova,
  • V. V. Voitkova,
  • A. B. Pyatidesyatnikova,
  • D. D. Bryukhova,
  • N. O. Kiseleva,
  • K. M. Korytov,
  • T. G. Kuznetsova,
  • Zh. V. Markevich

DOI
https://doi.org/10.29413/ABS.2020-5.5.3
Journal volume & issue
Vol. 5, no. 5
pp. 26 – 30

Abstract

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Background. Currently, during the COVID-19 pandemic, one of the most pressing healthcare problems is to ensure the safety of the population of the Russian Federation. There is insufficient information on the duration and intensity of post-infectious immunity in relation to SARS-CoV-2, especially in case of inapparent (without clinical signs), mild or latent forms of infection.Materials and methods. The study involved 99 volunteers with a laboratory confirmed PCR diagnosis of COVID-19 who were residents of the Irkutsk Region and of other regions of the Russian Federation and arrived to work in Bodaybo on a rotational basis. Also the study included 50 conditionally healthy people living in Irkutsk who had negative PCR results for SARS-CoV-2 RNA presence.Specific IgG and IgM antibodies to SARS-CoV-2 were detected in blood serum by enzyme-linked immunosorbent assay (ELISA) using test systems “ELISA anti-SARS-CoV-2 IgG” (FBUN SSC PMB, Obolensk, Russian Federation), “SARS-CoV-2-IgG-IFA-BEST” and “SARS-CoV-2-IgM-IFA-BEST” (Vector-Best, Novosibirsk, Russian Federation).Results. The results of a study of the humoral immunity of patients with asymptomatic and clinical forms of COVID-19 are presented. The data indicate the production of specific IgG in the blood serum of people in 2–3 weeks after SARSCov-2 infection and reaching its maximum level on the 20–21st day. The seroconversion rate was 94.9 %. It was shown that the geometric mean titer of antibodies in asymptomatic and mild forms of coronavirus infection did not differ statistically and amounted to 1:512 and 1:632, respectively. Higher titers of antibodies (1:1600) were detected in the moderate form.Conclusion. The research results can serve as a basis for studying the dynamics of changes in the indicators of the humoral immune response in patients with COVID-19 and for clarifying the duration of their post- infectious immunity in order to predict the development of the epidemic situation and to ensure the planning of specific prevention.

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