Background:
U.S. long-term care facilities have experienced a disproportionate burden of COVID-19 morbidity and mortality.
Methods:
We examined SARS-CoV-2 transmission among residents and staff in 60 long-term care facilities in Fulton County, Georgia, from March 2020 to September 2021. Using the Wallinga–Teunis method to estimate the time-varying reproduction number, R(t), and linear mixed regression models, we examined associations between case characteristics and R(t).
Results:
Case counts, outbreak size and duration, and R(t) declined rapidly and remained low after vaccines were first distributed to long-term care facilities in December 2020, despite increases in community incidence in summer 2021. Staff cases were more infectious than resident cases (average individual reproduction number, Ri = 0.6 [95%CI: 0.4-0.7] and 0.1 [95%CI: 0.1-0.2], respectively). Unvaccinated resident cases were more infectious than vaccinated resident cases (Ri = 0.5 [95%CI: 0.4-0.6] and 0.2 [95%CI: 0.0-0.8], respectively), but estimates were imprecise.
Conclusions:
COVID-19 vaccines slowed transmission and contributed to reduced caseload in long-term care facilities. However, due to data limitations, we were unable to determine whether breakthrough vaccinated cases were less infectious than unvaccinated cases. Staff cases were six times more infectious than resident cases, consistent with the hypothesis that staff were the primary drivers of SARS-CoV-2 transmission in long-term care facilities.
Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.
http://dlvr.it/SR2H2v
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