Course and Lethality of SARS-CoV2 Epidemic in Nursing Homes after Vaccination in Florence, Italy

Evidence on the effectiveness of SARS‐CoV2 vaccines in nursing home (NHs) residents is limited. We examined the impact of the BNT162b2 mRNA SARS‐CoV2 vaccine on the course of the epidemic in NHs in the Florence Health District, Italy, before and after vaccination. Moreover, we assessed survival and hospitalization by vaccination status in SARS‐CoV2‐positive cases occurring during the post‐vaccination period. We calculated the weekly infection rates during the prevaccination (1 October–26 December 2020) and post‐vaccination period (27 December 2020–31 March 2021). Cox analysis was used to analyze survival by vaccination status. The study involved 3730 residents (mean age 84, 69% female). Weekly infection rates fluctuated during the prevaccination period (1.8%–6.5%) and dropped to zero during the post‐vaccination period. Nine unvaccinated (UN), 56 partially vaccinated (PV) and 35 fully vaccinated (FV) residents tested SARSCoV2+ during the post‐vaccination period. FV showed significantly lower hospitalization and mortality rates than PV and UV (hospitalization: FV 3%, PV 14%, UV 33%; mortality: FV 6%, PV 18%, UV 56%). The death risk was 84% and 96% lower in PV (HR 0.157, 95%CI 0.049–0.491) and FV (HR 0.037, 95%CI 0.006–0.223) versus UV. SARS‐CoV2 vaccination was followed by a marked decline in infection rates and was associated with lower morbidity and mortality among infected NH residents.