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. 2021 May 10;193(19):E672-E680.
doi: 10.1503/cmaj.202756.

Risk factors for outbreaks of SARS-CoV-2 infection at retirement homes in Ontario, Canada: a population-level cohort study

Andrew P Costa  1 , Derek R Manis  2 , Aaron Jones  2 , Nathan M Stall  2 , Kevin A Brown  2 , Veronique Boscart  2 , Adriane Castellino  2 , George A Heckman  2 , Michael P Hillmer  2 , Chloe Ma  2 , Paul Pham  2 , Saad Rais  2 , Samir K Sinha  2 , Jeffrey W Poss  2
Affiliations

Risk factors for outbreaks of SARS-CoV-2 infection at retirement homes in Ontario, Canada: a population-level cohort study

Andrew P Costa et al. CMAJ. .

Abstract

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.

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Conflict of interest statement

Competing interests: Andrew Costa reports receiving support during the conduct of the study from the Juravinski Research Institute. Dr. Costa also reports receiving grants from the Public Health Agency of Canada and the Canadian Institutes of Health Research and payments or honoraria from CIHR and Florida Society for Post-Acute & Long-Term Care Medicine, outside the submitted work. Dr. Costa reports being a member of Ontario COVID-19 Congregate Care Setting Science Advisory Table Working Group, Ontario COVID-19 Science Advisory Table, Ontario Ministry of Health and the Government of Ontario, and is the Schlegel Chair in Clinical Epidemiology and Aging. George Heckman reports receiving fees from Merck for participation in an advisory board. Michael Himmer reports receiving support for attending a meeting. Adriane Castellino, Chloe Ma and Paul Pham report being employees of the Retirement Homes Regulatory Authority (RHRA), an independent, self-funded, not-for-profit regulator mandated by the Ontario government; members of RHRA’s Board of Directors include executives of Chartwell Retirement Residences, Diversicare Canada and Amica Senior Lifestyles, which represent the retirement home industry on the Board.. Derek Manis reports receiving Mitacs Accelerate Fellowship, during the conduct of this study, and student membership of the Board of Directors of the Justice Emmett Hall Memorial Foundation. Samir Sinha reports receiving consulting fees from Ontario Ministry of Health and Long-Term Care, and payment or honoraria for lectures, presentations or educational events from the Alberta Continuing Care Association, BC Care Providers Association, Canadian Association for Long-Term Care, Canadian Institutes of Health Research Best Brains Exchange Program on the Regulation of the Ontario Retirement Homes Sector, Long-Term Care Association of Manitoba, New Brunswick Association of Nursing Homes, Ontario Long-Term Care Association and the Ontario Retirement Communities Association. No other competing interests were declared.

Figures

Figure 1:
Figure 1:
Outbreaks of SARS-CoV-2 infection at retirement homes, by community-level ethnic concentration and public health unit region. Note: Public health unit regions with fewer than 5 retirement homes are excluded.
See this image and copyright information in PMC

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