[Impact of covid-19 vaccination on hospitalization in a third-level hospital.]

Objective: This study presents information on the evolution of severe cases of SARS-CoV-2 infection that required hospitalization since the beginning of vaccination in Spain. The objective was to know the impact of vaccination against COVID-19 on the hospitalization of patients with SARS-CoV-2 infection, hospital mortality and readmissions for this cause, and to describe the characteristics of vaccinated patients who required admission.

Methods: A retrospective, observational epidemiological study was conducted of all patients admitted with SARS-CoV-2 infection confirmed by a diagnostic test for active infection (PDIA) in a tertiary hospital, from January 2021 to June 2021. The incidence of admissions was calculated based on the vaccination status of the patients and age groups at different times according to the progress of the strategy of vaccination COVID-19.

Results: Between December 27, 2020 and June 30, 2021, 1,308 patients with positive PDIA were admitted to the University Hospital of Salamanca, of which 1,167 (89.2%) were not vaccinated, 129 (9.9%) had received one dose of vaccine and 12 (0.9%) were fully vaccinated. Of the latter, none were admitted to the ICU and 2 died.

Conclusions: Vaccination against COVID-19 has contributed to the decrease in hospitalizations, since February 2021, of older and institutionalized people. Fully vaccinated people have a lower risk of admission to the ICU and death. These data, together with the information available on recent cases of new SARS-CoV-2 infections in unvaccinated young people, are in favor of achieving high vaccination coverage of the entire population in the shortest possible time.