The impact of time since SARS-Cov-2 vaccination, age, sex and comorbidities on COVID-19 outcome in hospitalized patients with SARS-CoV-2 infection.

We evaluated the impact of COVID-19 vaccination on disease outcome in hospitalized patients with SARS-CoV-2 infection with a prospective study. 745 vaccinated and 451 unvaccinated patients consecutively admitted to a COVID-19 Hospital from 1st September 2021 to 1st September 2022 were included. Compared with unvaccinated cases, vaccinated patients were older, had more comorbidities, but had a lower risk of O2 need (odds ratio, OR, 0.46; 95 % CI 0.32-0.65) by logistic regression analysis adjusted for age, sex, comorbidity and WHO COVID-19 Clinical Progression Scale at admission. The ORs for O2 need were 0.38 (0.24-0.61), 0.50 (0.30-0.83) and 0.57 (0.34-0.96) in patients vaccinated 14-120, 121-180 and > 180 days prior to hospitalization, respectively. An anti-spike Ig titer higher than 5000 U/ml was associated with a reduced risk of O2 need (OR 0.52; 95 % CI 0.30-0.92). This study shows that COVID-19 vaccination has a significant impact on COVID-19 outcomes in hospitalized patients.