Study Finds SARS-CoV-2 Booster Vaccination Lowers Infections, Hospitalizations, and Deaths in Nursing Homes

Booster vaccination was associated with lower rates of SARS-CoV-2 infection, hospitalization, and death among nursing home residents in a recent study published in JAMA Network Open.

Morbidity and mortality related to COVID-19 has been high in nursing homes throughout the pandemic. In response to surges in infections with the Delta variant of SARS-CoV-2 during summer and autumn of 2021, the CDC recommended that high-risk individuals who received a 2-dose mRNA vaccine series should receive a booster dose. However, there are limited data on the efficacy of boosters for preventing infection and death in nursing home residents, who are particularly vulnerable to SARS-CoV-2–associated morbidity and mortality.

The study used electronic health record data from 2 large, multi-state long-term care systems to estimate vaccine effectiveness (VE) in individuals who received both an initial series of mRNA vaccines and a booster dose versus those who received a primary vaccine series but did not receive a booster dose.

“Nursing homes are an optimal environment for measurement of VE because of residential stability, systematic documentation of immunizations (including boosters), and frequent testing for SARS-CoV-2,” the authors wrote.

The study followed long-term nursing home residents, defined as living in a facility for at least 100 days, for up to 12 weeks after booster vaccination to track incidences of confirmed SARS-CoV-2 infection, hospitalization, or death. The VE estimation considered the ratio of cumulative incidences in the boosted cohort compared with the unboosted cohort.

A total of 10,949 residents from 202 community nursing homes within the Genesis HealthCare system and 4321 residents from 128 Veterans Health Administration community living centers (VHA CLCs) were included in the study. All residents had completed an initial 2-dose series of an mRNA vaccine. A total of 8332 residents in the Genesis HealthCare system (system 1) and 3289 in the VHA CLCs (system 2) were boosted. Results for each health system were reported separately, primarily due to data use agreements that prevented data exportation from their respective secure servers.

Residents who were boosted showed reduced incidences of SARS-CoV-2 infection in both health systems. In system 1, boosted individuals were 37.7% less likely to be infected, and in system 2, boosted residents were 57.7% less likely to get infected. The incidence of hospitalization was 74.4% lower in in boosted patients within system 1, and 64.1% lower in boosted patients in system 2.

The estimated VE for SARS-CoV-2–death was 87.9% in system 1, but boosted individuals in system 2 were not at a significantly lower risk of death compared with unboosted residents. There was a slight reduction in death among boosted patients, however. Boosted residents in system 1 showed an 80.3% reduction in the combined end point of SARS-CoV-2–associated hospitalization or death, while boosted patients in system 2 showed a 63.8% reduction in the combined end point.

The 2 nursing home populations were significantly different in size and population demographics, but each demonstrated the efficacy of mRNA SARS-CoV-2 vaccine boosters for the overall high-risk nursing home population. While data in this population are sparse, the cohort study found much lower risks of SARS-CoV-2 infection, hospitalization, and death among the included nursing home populations. These findings emphasize the importance of SARS-CoV-2 booster vaccinations in this population.

Reference

McConeghy KW, Bardenheier B, Huang AW, et al. Infections, hospitalizations, and deaths among US nursing home residents with vs without a SARS-CoV-2 vaccine booster. JAMA Netw Open. 2022;5(12):e2245417. Published 2022 Dec 1. doi:10.1001/jamanetworkopen.2022.45417