Aims: An observational study of a retrospective cohort was performed to assess the impact of influenza vaccination (IV) on the risk of SARS-CoV-2 infection in a population of middle-aged people for 8 weeks after IV and compared with an unvaccinated group.Patients and methods: Data from 1098 middle-aged patients (53.7 ± 4.7 years) after IV and 1205 unvaccinated patients (50.1 ± 6.8 years) were analyzed based on medical documentation. The inclusion criteria were age between 40 - 60 years and IV in the period from 1-30 September 2020. The incidence of infection with SARS-CoV-2 was confirmed by PCR and the classification of ICD-10 (U07.1).Results and conclusions: After IV, patients had significantly fewer SARS-CoV-2 infections than the unvaccinated patients (P = .017). The hazard ratio was 0.74 (95% CI: 0.54-0.89). IV may partially reduce the risk of SARS-CoV-2 infection.
Keywords: SARS-CoV-2; Vaccine; comparative effectiveness; immunotherapy; influenza.