Effect of SARS-CoV-2 vaccination in a vulnerable COVID-19 cohort: a real-life experience in an Italian Hospital

Clinical trials demonstrated that SARS-CoV-2 vaccines reduce COVID-19-related mortality and morbidity. We describe the effect of vaccination on COVID-19-patients admitted at our hospital. Retrospective, single-center study conducted in Genoa, Italy, including patients >= 18years hospitalized for COVID-19 from May to December 2021. Demographical and clinical data were collected, vaccinated (group-A) and not-vaccinated (group-B) patients were compared. Impact of vaccination on mortality, ICU admission, and oxygen need was studied using Cox proportional hazards and logistic regression models after adjusting for propensity scores. Overall, 395 patients SARS-CoV-2 infected were included, of which 150 (38%) were vaccinated and 245 (62%) were not vaccinated. Patients in group-A were older, more disable, and with higher morbidity. Overall, 64 patients (16%) died within 30 days from admission, 34 in Group A (23%), and 30 in group B (12%). However, no statistically significant differences were observed (group-A versus group-B: HR 0.83, 95% CI 0.49-1.40, p = 0.483). On the other hand, vaccination was protective in terms of ICU admission (OR = 0.23, p = 0.046) and oxygen need (OR = 0.33, p = 0.008). Our study confirms that SARS-CoV-2 vaccination reduces morbidity among patients hospitalized for COVID-19. The still high mortality in our cohort of vaccinated individuals could be partially due to vulnerable conditions of our patients.