The Role of Staff in Transmission of SARS-CoV-2 in Long-Term Care Facilities: Analysis of COVID-19 Cases in Fulton County, Georgia, March 2020 to September 2021

Background: U.S. long-term care facilities (LTCFs) have experienced a disproportionate burden of COVID-19 morbidity and mortality. Methods: We examined SARS-CoV-2 transmission in 60 LTCFs 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) . Findings: Case counts, outbreak size/duration, and R(t) declined rapidly and remained low after vaccines were first distributed to LTCFs in December 2020, despite increases in community incidence in summer 2021 . Staff cases were more infectious than resident cases (average individual reproduction number, R i = 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 (R i = 0·5 [95%CI: 0·4-0·6] and 0·2 [95%CI:0-0·8], respectively), but estimates were imprecise. Interpretation: COVID-19 vaccines slowed transmission and contributed to reduced case load in LTCFs. 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, suggesting that staff were important drivers of SARS-CoV-2 transmission in LTCFs . Funding Information: This work was supported by the Agency for Healthcare Research and Quality (R01 HS025987), the National Science Foundation (2032084), and the Emory Covid-19 Response Collaborative, which is funded by a grant from the Robert W. Woodruff Foundation. NRG was supported by the US National Institutes of Health (K24AI114444). JZ was supported by award 1 U01 IP001138-01 from the Centers for Disease Control and Prevention. AC, SS and NRG are supported by a contract from the Fulton County Board of Health. We thank the Georgia Department of Public Health and the Fulton County Board of Health for collaborating on and supplying data for this project. The contents herein are those of the authors and do not necessarily represent the official views of, nor an endorsement by, the Georgia Department of Public Health or the Fulton County Board of Health. Declaration of Interests: AC is an epidemiology consultant with the Fulton County Board of Health. All other authors have nothing to declare.