Проблемы особо опасных инфекций (Oct 2020)

Herd Immunity to SARS-CoV-2 among the Population in Saint-Petersburg during the COVID-19 Epidemic

  • A. Yu. Popova,
  • E. B. Ezhlova,
  • A. A. Mel’nikova,
  • N. S. Bashketova,
  • R. K. Fridman,
  • L. V. Lyalina,
  • V. S. Smirnov,
  • I. G. Chkhindzheriya,
  • T. A. Grechaninova,
  • K. A. Agapov,
  • N. A. Arsent’eva,
  • N. A. Bazhenova,
  • O. K. Batsunov,
  • E. M. Danilova,
  • E. V. Zueva,
  • D. V. Komkova,
  • R. N. Kuznetsova,
  • N. E. Lyubimova,
  • A. N. Markova,
  • I. V. Khamitova,
  • V. I. Lomonosova,
  • V. V. Vetrov,
  • A. M. Milichkina,
  • V. G. Dedkov,
  • A. A. Totolyan

DOI
https://doi.org/10.21055/0370-1069-2020-3-124-130
Journal volume & issue
Vol. 0, no. 3
pp. 124 – 130

Abstract

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The first case of COVID-19 was diagnosed in St. Petersburg on March 2, 2020; the period of increase in the incidence lasted for 10 weeks, the maximum rates were recorded in mid-May, and subsequently there was a statistically significant decrease in the incidence.Objective: to determine the level and structure of community immunity to SARS-CoV-2 among the population of St. Petersburg during the period of intensive spread of COVID-19.Materials and methods. Selection of volunteers for the study was carried out through interviewing and randomization. The exclusion criterion was active COVID-19 infection at the time of the survey. 2713 people aged 1 to 70 years and above were examined for the presence of specific antibodies to SARS-CoV-2. Antibodies were detected by enzyme immunoassay.Results and discussion. Studies have shown that in St. Petersburg, in the active phase of COVID-19 epidemic, there was a moderate seroprevalence to SARS-CoV-2, which amounted to 26 %, against the background of a high frequency (84.5 %) of asymptomatic infection in seropositive individuals who did not have a history of COVID-19 disease, positive PCR result and ARI symptoms on the day of examination. The maximum indicators of herd immunity were established in children 1–6 years old (31.1 %), 7–13 years old (37.7 %) and people over 70 years old (30.4 %). Differences in the level of seroprevalence in the age groups of 18–49 years are statistically significant. The highest level of seroprevalence was found among the unemployed (29.7 %), healthcare workers (27.1 %), education sector (26.4 %) and business sector personnel (25 %). In convalescents, COVID-19 antibodies are produced in 75 % of cases. In individuals with positive result of PCR analysis carried out earlier, antibodies are detected in 70 % of the cases. The results of the study of herd immunity to SARS-CoV-2 are essential to forecast the development of the epidemiological situation, as well as to plan measures for specific and non-specific prevention of COVID-19.

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