Effect of influenza, pneumococcal and SARS-CoV-2 vaccination on the incidence and severity of COVID-19 in health care workers at a single institution (epidemiologic study)
Authors:   I.M.Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russian Federation, Kostinov M.P. ,   Novorossiysk Clinical Center of the Federal Medical and Biological Agency, Novorossiysk, Russian Federation, Nastaeva N.Yu. ,   I.I.Mechnikov Research Institute of Vaccines and Serums, Moscow, Russian Federation, Nikityuk N.F. ,   I.M.Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russian Federation,   Novorossiysk Clinical Center of the Federal Medical and Biological Agency, Novorossiysk, Russian Federation, Linok A.V. ,   Novorossiysk Clinical Center of the Federal Medical and Biological Agency, Novorossiysk, Russian Federation, Loktionova M.N. ,   Novorossiysk Clinical Center of the Federal Medical and Biological Agency, Novorossiysk, Russian Federation,   Central Research Institute of Epidemiology, Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing, Moscow, Russian Federation, Abdullayeva G.M. ,   Asfendiyarov Kazakh National Medical University, Almaty, Republic of Kazakhstan, Sagatbaeva N.А. ,   Asfendiyarov Kazakh National Medical University, Almaty, Republic of Kazakhstan, Soloveva I.L. ,   Ulyanovsk State University, Ulyanovsk, Russian Federation
Published: September 2024

Objective. To study the effect of influenza, pneumococcal and SARS-CoV-2 vaccination on the incidence and severity of COVID-19 course in health care workers. Patients and Methods. We examined 547 health care workers divided into group 1 (no history of influenza and pneumococcal vaccination, n = 281) and groups vaccinated between August and October 2020 (before SARS-CoV-2 epidemic II): Group 2 against influenza (n = 98), Group 3 against pneumococcal infection (n = 60), and Group 4 against influenza and pneumococcus (n = 108). Between March and August 2021 (before the SARS-CoV-2 epidemic III outbreak), 98.6% of all employees were vaccinated against COVID-19. We compared COVID-19 incidence rates during Periods II and III epidemic rises (2020–2022) as a function of influenza and pneumococcal vaccination. Results. It was found that with combined vaccination against influenza and pneumococcal infection in the group of medical workers at high risk of infection, the risk of COVID-19 morbidity within 4–5 months was 2 times lower (1.6% vs. 13.2%, p < 0.05) compared to the unvaccinated. Comparative data on COVID-19 incidence in the II and III periods of epidemic rises showed that COVID-19 in medical workers in the III period was registered 36.1% lower in comparison with the index in the II period – 11.2 and 7.1%, respectively (p < 0.05). We found that when comparing II and III periods of epidemic rises among medical workers, the proportion of persons with COVID-19 with moderate forms of disease who received combined vaccination against influenza and pneumococcal infection decreases more than 2-fold (p < 0.05), including in the category with a high risk of infection. Conclusion. The presented data indicate a positive effect of combined vaccination against pneumococcal infection and influenza on the incidence and severity of COVID-19. The proposed approach can be used in public health practice as a method of nonspecific prevention of COVID-19 and other acute respiratory viral infections. Key words: influenza vaccine, pneumococcal vaccine, combined vaccination, epidemic rise, COVID-19