PT  - JOURNAL ARTICLE
AU  - Costa, Andrew P.
AU  - Manis, Derek R.
AU  - Jones, Aaron
AU  - Stall, Nathan M.
AU  - Brown, Kevin A.
AU  - Boscart, Veronique
AU  - Castellino, Adriane
AU  - Heckman, George A.
AU  - Hillmer, Michael P.
AU  - Ma, Chloe
AU  - Pham, Paul
AU  - Rais, Saad
AU  - Sinha, Samir K.
AU  - Poss, Jeffrey W.
TI  - Risk factors for outbreaks of SARS-CoV-2 infection at retirement homes in Ontario, Canada: a population-level cohort study
AID  - 10.1503/cmaj.202756
DP  - 2021 May 10
TA  - Canadian Medical Association Journal
PG  - E672--E680
VI  - 193
IP  - 19
4099  - http://www.cmaj.ca/content/193/19/E672.short
4100  - http://www.cmaj.ca/content/193/19/E672.full
SO  - CMAJ2021 May 10; 193
AB  - BACKGROUND: The epidemiology of SARS-CoV-2 infection in retirement homes (also known as assisted living facilities) is largely unknown. We examined the association between home-and community-level characteristics and the risk of outbreaks of SARS-CoV-2 infection in retirement homes since the beginning of the first wave of the COVID-19 pandemic.METHODS: We conducted a population-based, retrospective cohort study of licensed retirement homes in Ontario, Canada, from Mar. 1 to Dec. 18, 2020. Our primary outcome was an outbreak of SARS-CoV-2 infection (≥ 1 resident or staff case confirmed by validated nucleic acid amplification assay). We used time-dependent proportional hazards methods to model the associations between retirement home– and community-level characteristics and outbreaks of SARS-CoV-2 infection.RESULTS: Our cohort included all 770 licensed retirement homes in Ontario, which housed 56 491 residents. There were 273 (35.5%) retirement homes with 1 or more outbreaks of SARS-CoV-2 infection, involving 1944 (3.5%) residents and 1101 staff (3.0%). Cases of SARS-CoV-2 infection were distributed unevenly across retirement homes, with 2487 (81.7%) resident and staff cases occurring in 77 (10%) homes. The adjusted hazard of an outbreak of SARS-CoV-2 infection in a retirement home was positively associated with homes that had a large resident capacity, were co-located with a long-term care facility, were part of larger chains, offered many services onsite, saw increases in regional incidence of SARS-CoV-2 infection, and were located in a region with a higher community-level ethnic concentration.INTERPRETATION: Readily identifiable characteristics of retirement homes are independently associated with outbreaks of SARS-CoV-2 infection and can support risk identification and priority for vaccination.