Course and Lethality of SARS-CoV-2 Epidemic in Nursing Homes after Vaccination in Florence, Italy

Giulia Rivasi,Aldo Lo Forte,Sante Giardini,Claudia Cosma,Guglielmo Bonaccorsi,Andrea Ungar,Letizia Martella,Serena Boni,Lorenzo Baggiani,Matteo Bulgaresi,Enrico Mossello,Primo Buscemi,Paolo Carrai,Irene Marozzi,Daniela Balzi,Giacomo Fortini,Enrico Benvenuti,Lorenzo Stacchini,Andrea Crociani,Riccardo Barucci,Gabriele Vaccaro,Cecilia Piga,Chiara Lorini,Giulia Bandini,Simone Pupo,Giulia Bulli,Giancarlo Landini,Eleonora Barghini,Antonio Faraone,I Del Lungo ,Sebastiano Gangemi

doi:10.3390/vaccines9101174

Abstract

Evidence on the effectiveness of SARS-CoV-2 vaccines in nursing home (NHs) residents is limited. We examined the impact of the BNT162b2 mRNA SARS-CoV-2 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-CoV-2-positive cases occurring during the post-vaccination period. We calculated the weekly infection rates during the pre-vaccination (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 pre-vaccination 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 SARS-CoV-2+ 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-CoV-2 vaccination was followed by a marked decline in infection rates and was associated with lower morbidity and mortality among infected NH residents.

Highlights

The COVID-19 pandemic has dramatically affected nursing home (NH) residents [1,2,3,4], calling for the early vaccination of this vulnerable population.It is known that the immune response is reduced at an advanced age even in healthy older people, due to age-related changes in immune functions which are commonly referred to as immunosenescence [5]
Among 3730 SARS-CoV-2-naïve residents living in Florence Health District NHs as of 1 October 2020, a total of 1658 cases of SARS-CoV-2 infections were confirmed during the whole study period
Trend is in Figure 1, in in Figure comparison with new SARS-CoV-2 cases reported in the general illustrated

Summary

Introduction

The COVID-19 pandemic has dramatically affected nursing home (NH) residents [1,2,3,4], calling for the early vaccination of this vulnerable population.It is known that the immune response is reduced at an advanced age even in healthy older people, due to age-related changes in immune functions which are commonly referred to as immunosenescence [5]. In the NH setting, multimorbidity, medications and poor nutritional status may contribute to further impairing immune responses, thereby hampering vaccine effectiveness. The results of clinical trials on SARS-CoV-2 vaccines have reported comparable efficacy in older and younger adults [9,10,11]. Limited post-authorization data are available on SARS-CoV-2 vaccine efficacy and effectiveness in NH residents [12], and some preliminary observations suggest a blunted antibody response in this population [15,16]. Given these premises, the effects of SARS-CoV-2 vaccine in the NH setting remain largely unexplored

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