Analysis of the Risk of COVID-19 in the Post-Vaccination Period Based on the Results of a Multicenter Study — a Survey of Medical Workers

Abstract

Background. One of the vulnerable categories of the population during the COVID-19 pandemic has become employees of medical and educational institutions. Timely and properly organized prevention, based on anti-epidemic measures based on vaccination, is necessary not only to reduce the incidence of the disease, but primarily to reduce the severity in case of its occurrence, reduce the risk of hospitalization. Understanding the effectiveness of preventing SARS-CoV-2 infections among healthcare workers is a critical component of occupational health and safety policy and strategy.
 Aim — analysis of the incidence of COVID-19 after vaccination among medical staff and teaching staff of medical higher educational institutions.
 Methods. In the period from January to March 2022, a cross-sectional retrospective single-stage online study was conducted (anonymous questionnaires posted on the Anketologist platform). The survey was completed by 6032 respondents (82% efficiency). According to the criteria, 2114 respondents were excluded from the study. The analysis was carried out according to the questionnaires of 3918 respondents, including an assessment of the incidence after vaccination (n = 3668 respondents).
 Results. Fell ill after a double vaccination for 5 months — 663 (16.9%). Unvaccinated respondents reported that within 5 months. prior to the survey, 116 (46.4%) had a laboratory-confirmed new coronavirus infection. Lack of vaccination increased the risk of SARS-CoV-2 (OR 1.78 ± 0.14; 95% CI: 1.34–2.36). Efficiency within 5 months post-vaccination period was 55.5% (95% CI: 42.2–57.7%) for Sputnik V; 71.9% (95% CI: 68.1–85.4%) — Sputnik Light. It was found that gender and age were not a risk factor for the onset of the disease in the post-vaccination period. The presence of a history of previous COVID-19 increased the risk of disease in the post-vaccination period in individuals under 35 years of age (OR 2.323 ± 0.102; 95% CI: 1.903–2.836), aged 36–64 years (OR 2.547 ± 0.086; 95% CI: 2.150–3.016), older than 65 years (OR 1.323 ± 0.280; 95% CI: 0.764–2.290). Respondents with a history of a combination of chronic cardiovascular pathology and past COVID-19 had a higher risk of getting sick in the post-vaccination period (OR 1.338 ± 0.160; 95% CI: 0.977–1.832).
 Conclusion. According to the questionnaire, an important factor affecting the risk of COVID-19 in the post-vaccination period is the presence of SARS-CoV-2 before vaccination, which can increase the chance of developing the disease in the presence of other risk factors (chronic pathology, age, smoking, alcohol consumption).