Real-world Evidence of COVID-19 Vaccine Effectiveness Against COVID-19 Hospitalization: the Case-control Study in St. Petersburg, Russia

This is an observational case-control study to evaluate COVID-19 vaccine effectiveness against hospitalisation with COVID-19 related conditions in St. Petersburg, Russia. Two sets of cases and control will be retrospectively analyzed to compare vaccination proportions and other characteristics to infer vaccine effectiveness from odds ratios. The first set of cases will be extracted from the data on hospitalisation of patients with COVID-19 to First Pavlov State Medical University of Saint-Petersburg hospitals, and controls will be patients hospitalised with other conditions. The second set of cases and controls will be based on patients referred to Medical Institute named after Berezin Sergey for computed tomography. Cases will be patients with positive SARS-CoV-2 status computed tomography confirmed pneumonia or patients referred to hospitalisation, and control will be patients without pneumonia and not referred to hospitalisation.