Researchers in Canada explore risks of SARS-CoV-2 transmission in retirement homes

A year on since its emergence, the world continues to grapple with the coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). One of the highest risk areas of SARS-CoV-2 breakout has been retirement homes as among those most vulnerable to severe or critical COVID-19 are the elderly and those with underlying medical conditions.

Researchers at the McMaster University, Canada, have found that the higher the population in retirement homes, the higher the risk of COVID-19 outbreaks. Moreover, they found that retirement homes in a community with a higher ethnic concentration are also more likely to face COVID-19 outbreaks.

High risk of COVID-19

Early in the pandemic, scientists and clinicians taking care of COVID-19 patients observed one thing: the elderly and those with comorbidities were at a higher risk of developing severe COVID-19 symptoms than younger people.

As time passed, lockdown measures were implemented, specifically barring older adults from leaving their homes to prevent infection.

Apart from older adults, people with comorbidities or underlying health conditions are also at a higher risk of severe COVID-19 and death. These include people with cardiovascular disease, hypertension, kidney failure, diabetes, obesity, and those who have weakened immune systems, such as cancer patients undergoing chemotherapy.

Retirement homes

Older adults who are frail living in congregate care settings have been at the center of the coronavirus pandemic in Canada and other countries. Long-term care facilities have been the subject of scientific and public interest due to COVID-19 outbreaks.

The study, published on the pre-print medRxiv* server, focused on the risk factors associated with COVID-19 outbreaks in retirement homes or long-term care facilities.

The researchers conducted a study of licensed retirement homes in Ontario, Canada, between March and September 2020. Overall, the team included all 770 licensed retirement homes in the area, which housed 56,491 residents.

What the study found

There have been 172 COVID-19 retirement home outbreaks involving 1,045 residents and 548 staff in the study period. The COVID-19 cases were distributed unevenly across retirement homes, with over 1,590 resident and staff cases occurring in 77 homes.

About 90% of the outbreaks occurred before June 2020, and almost half of all outbreaks involved both staff and resident cases.

Retirement homes with one or more coronavirus outbreaks were more likely to have a larger capacity, have external care providers that enter the facility daily, part of a corporate-owned chain, have more services available, and located in larger communities with a higher ethnic concentration compared to homes without outbreaks.

The study findings support that the incidence of COVID-19 is associated with large chains and retirement homes' size. There is also a strong link between retirement home outbreaks and the 14-day rolling incidence of COVID-19 in the surrounding public health region.

With the COVID-19 transmission occurring in households and public areas, retirement homes with a high population are at a higher risk of experiencing outbreaks.

Retirement homes with more than 100 residents had more than a five-fold increase in the risk of an outbreak. Bigger retirement homes require more staff, increasing the number of potential individuals who unknowingly carry SARS-CoV-2 into homes.

The majority of retirement home outbreaks happened during the first wave of the pandemic when visitors were restricted. It is possible that staff and care providers were the primary vectors for transmitting COVID-19 infection into retirement homes.

The lack of an adjusted association between the external care providers and COVID-19 outbreak might be explained by the lack of variability between retirement homes of the same size," the team explained.

They added that homes that offered more services had a two-fold increased risk for a coronavirus outbreak. This may be due to the additional exposure to SARS-CoV-2 due to more lengthy interactions between residents and health care providers or staff members.

The team also observed a link between the levels of ethnic concentration in the community surrounding the retirement home and the risk of a COVID-19 outbreak. In a report by Public Health Ontario, communities with ethno-culturally dense populations experience disproportionately higher rates of COVID-19.

"Increased ethnic concentration of the community surrounding a retirement home is associated COVID-19 outbreaks, with an uncertain mechanism," the team concluded. Further research in the area may elucidate the underpinning causes of this increased risk.

The researchers emphasize how "identifying and understanding observed differences in COVID-19 outbreaks across retirement homes" may inform risk identification and prevention measures.

Over the past few weeks, Canada has reported surging COVID-19 cases. The country has over 464,000 cases and more than 13,000 deaths.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:
Angela Betsaida B. Laguipo

Written by

Angela Betsaida B. Laguipo

Angela is a nurse by profession and a writer by heart. She graduated with honors (Cum Laude) for her Bachelor of Nursing degree at the University of Baguio, Philippines. She is currently completing her Master's Degree where she specialized in Maternal and Child Nursing and worked as a clinical instructor and educator in the School of Nursing at the University of Baguio.


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