Retirement homes with large numbers of residents and staff suffered a threefold greater risk of being hit by COVID-19 last year, according to a McMaster University-led study.
Researchers say the increased risk was likely because of more staff coming in and out of a home when providing care. Homes that provided nine or more services had a 2.5-fold increased risk of an outbreak, while those co-located with a long-term care facility had a 1.6-fold increased risk.
Being part of a large chain and located in areas with higher ethno-culturally diversity also increased the risk of outbreaks, says the study, published in the Canadian Medical Association Journal.
"Outbreaks of COVID-19 infection surged in retirement homes during the first and second waves in Canada and the US, and there has been limited examination in the literature beyond early reports of case surveillance," said Andrew Costa, assistant professor at McMaster’s Department of Health Research Methods, Evidence and Impact.
Researchers used data gathered from March 1 to Dec. 18, 2020, from 770 retirement homes in Ontario with a total population of more 56,000 residents. The resident population sample was similar to those living in long-term care facilities.
Of the retirement homes surveyed in this time frame, 273 suffered at least one COVID-19 outbreak.
The study says a subset of Ontarian retirement homes were severely affected by the pandemic, with fatalities approaching those of long-term care homes.
As of April 11, retirement homes accounted for eight per cent of all COVID-19 deaths in Ontario.The study says risk factors, such as high staff traffic, behind COVID-19 outbreaks in retirement homes will help inform both provincial and local government vaccination policies, as with the long-term care sector.
However, one simple step can reduce the risk of potentially lethal outbreaks in the meantime.
"Limiting the number of different staff providing care and services within retirement homes and a reduction in staff connectivity between settings are modifiable factors that may reduce the risk of future outbreaks of COVID-19,” the study authors say.