Introduction: To date, issues related to the protection of medical workers from COVID-19 infection, including immunological protection, are of particular interest. The aim of the study was to assess the risk of a new coronavirus infection depending on the initial immune status and occupational group during a 150-day follow-up. Materials and Methods: The study of immune response to the SARS-CoV-2 virus was carried out in the frame of the large-scale program ruled by the state body responsible for the epidemiological surveillance. From the regional sample, medical workers (301 people) without a previous history of the new coronavirus infection at the time of biosampling (June 2020) were selected. The comparison group included 52 workers and was formed from engineering and technical personnel not employed in medical institutions. Within 150 days from the blood sampling, cases of the new coronavirus infection were monitored based on the patient's inclusion in the Federal Register of COVID-19 patients. To estimate the adjusted hazard ratios, Cox proportional hazards models was applied. Results and Conclusions: In 150-day follow-up it was revealed that the probability of remaining healthy by the end of the follow-up was the lowest among doctors from medical and preventive institutions (MPI) that did not serve as temporary hospitals: HR 2,33 [95% CI 0,95;5,70], which may be due to both insufficient anti-epidemic measures and the peculiarities of the immune response and approaches for its evaluation. The risk of COVID-19 in seronegative individuals was higher, but without statistical significance.
Risk of COVID-19 among different groups of healthcare workers: a 150-day follow-up study