Risks of adverse outcomes in COVID-19 patients and vaccination status in a secondary hospital in Spain

INTRODUCTION: In December 2020, vaccination against SARS-CoV-2 started in Spain. Until March 2022, 91.1% of the target population was vaccinated. The objective of the study is to describe the characteristics of patients with SARS-CoV-2 infection, the risk of serious outcomes and their vaccination status. MATERIAL AND METHODS: Retrospective longitudinal analytical observational study. Demographic characteristics and outcomes of COVID-19 infections and vaccination history from 01/01/2021–08/10/2021 were collected from electronic medical records and the Unified Vaccination Registry. Data analysis was performed with Excel and Stata 16. RESULTS: 4161 COVID-19 cases were detected; of which 185 (4.5%) had received a complete vaccination schedule. The most affected age group was 80–89 years (34.1%). 1697 patients were hospitalized, of whom 78 (4.6%) had been vaccinated against SARS-CoV-2. No patient admitted to the ICU had a history of vaccination. The mean hospitalization time in unvaccinated patients was 11 days (95% CI -41.54–63.54) compared to 8.5 days (95% CI 7.04–9.96) in vaccinated patients. The relative risk of hospitalization in vaccinated patients compared to unvaccinated patients for the age group 40 to 59 years was 0.29 (95% CI 0.11–0.72) and 0.77 (95% CI 0.67–0). 0.90) for people over 60 years of age. CONCLUSIONS: The risk of hospitalization and death was lower in vaccinated patients compared to unvaccinated patients in the age groups 40–59 and older than 60 years. This finding supports current clinical evidence.