Impact of vaccination on the spread of SARS-CoV-2 infection in north-east Italy nursing homes. A propensity score and risk analysis

Abstract

Background In the Veneto Region, 421,000 coronavirus 2019 disease (COVID-19) cases and 11,000 deaths have been reported since 21 February 2020. The pandemic spread particularly in nursing homes (NH). Objective This study estimated the impact of SARS-CoV-2 infection among NH residents, focusing on the risk of hospitalisation and death due to COVID-19 compared with the general older population. It also provided evidence of risk changes over time. Methods Older people, resident in Veneto, were enrolled from the regional registry of the population. We collected also information about demographic characteristics, chronic diseases, COVID-19 positivity, NH institutionalization, hospitalisation and date of death. Patients were assigned to NH or non-NH residents groups through a propensity score 1:1 matching. The follow-up period was defined as 21 February 2020 – 3 May 2021 and then divided into three waves. Risk ratios (RRs) and 95% confidence interval were estimated by using Poisson models with robust estimation of variance. Results NH residents showed a higher risk of COVID-19 infection (RR = 6.28; 6.03–6.54), hospitalisation for COVID-19 (RR = 2.20; 2.05–2.36) and death with COVID-19 (RR = 6.07; 5.58–6.61). Conclusion NH residents shared common spaces with other patients and healthcare professionals and were more exposed to infections. Nonetheless, in Italy from late December 2020 to May 2021, 95% of NH residents and their healthcare professionals received at least one vaccine dose and RRs for all outcomes decreased in NH.

Veneto Region dementia-related mortality during the COVID-19 pandemic: multiple causes of death and time series analysis

“…22 A previous study on the risk of infection, hospitalization and mortality due to COVID-19 in nursing home residents, compared to matched non-nursing home counterparts has shown how people in this setting were at a significantly increased risk of any of the three outcomes, especially in the first and second pandemic waves. 23 …”

“…Only after the implementation of the vaccination campaign, starting from nursing home residents and personnel, the impact of subsequent pandemic waves was reduced, at least in terms of mortality. 23 …”

Protective effects of prior third dose mRNA vaccination in rural nursing home residents during SARS‐CoV‐2 outbreaks

“…7,8 To date, most studies on vaccine efficacy in NHs were performed prior to the emergence of the BA.2 variant of SARS-CoV-2 (Omicron) as the dominant strain, and before a third vaccine dose was recommended. [2][3][4][5]9 Moreover, many of these nursing home studies looked at primarily urban as opposed to rural NH populations. 10,11 This report analyzes the effect of prior vaccination of NH residents during recent outbreaks of SARS-CoV-2 in NHs in rural Manitoba, Canada.…”

“…To date, most studies on vaccine efficacy in NHs were performed prior to the emergence of the BA.2 variant of SARS‐CoV‐2 (Omicron) as the dominant strain, and before a third vaccine dose was recommended 2–5,9 . Moreover, many of these nursing home studies looked at primarily urban as opposed to rural NH populations 10,11 .…”

Vaccination of Elderly People Affected by Chronic Diseases: A Challenge for Public Health

“…Nevertheless, a 2021 study estimated that in Apulia, an Italian Region with 4 million inhabitants, a proportion of citizens with at least one underling condition to be around 65%; this proportion increases with increasing age [ 23 ]. A 2022 Italian study [ 24 ] reported that, among 852,211 living subjects residing in Veneto Region and aged between 70 and 100 years, the prevalence of subjects with at least one chronic disease ranged from 69% to 74%. Of course, additional studies are needed to estimate these data on whole the Italian population aged 65+ years.…”