Epidemiology of COVID‑19 and Canadian Subpopulations

Immigrants and refugees, people with a substance use disorder, and the homeless seem to be disproportionately affected by COVID-19. Risk factors for severe disease in Canada include age, male sex, and pre-existing medical conditions (i.e., diabetes, high blood pressure, chronic lung disease and obesity). People with a substance use disorder and the homeless were also at increased risk of severe outcomes. The highest proportion at risk of COVID‑19 severe outcomes were those ages 80-years and older followed by the First Nations, Métis, and those living in low-income households. Rates of severe COVID‑19 health outcomes were lower among visible minority groups as described in the reports as Arab/West Asian Canadians, East/Southeast Asian Canadians, and Black Canadians compared to those identified as White. By contrast, COVID‑19 mortality rates are higher in Canadian neighbourhoods that have a higher proportion of visible minority groups. Neighbourhoods’ ethno-cultural make-up were associated with COVID‑19 mortality rates in Quebec, Ontario, Alberta, and British Columbia. However, these results should be interpreted cautiously given that they focus on sociodemographic characteristics.

There is a lack of high-level evidence (i.e., evidence from systematic reviews, meta-analysis, or rapid reviews) focused on the epidemiology of specific Canadian subpopulations. These include vulnerable and visible minority populations, high-risk populations, and ethno-cultural neighborhoods. Future high-level research may want to consider focusing on conducting syntheses restricted to countries with settings and contexts that share similar Canadian subpopulations – i.e., with focus on Organization for Economic Co-operation and Development (OECD) countries – as we wait for Canadian research to be completed. Further, there is a need for better standardized data collection, analysis, and written reports by Canada’s provinces and territories related to sub-populations and risk factors identified during the SARS-CoV-2 testing (i.e., ethnicity, race, sex, language and culture, people with disability, and geography).

Currently, there are eight ongoing cohort Canadian studies that have yet to publish results. There is one non-Canadian living systematic review focused on risk of infection in people living with asthma.

The upcoming studies in Canada are focused on:

• COVID‑19 transmission in the Hutterites, children (Mark Loeb, McMaster University);

• Chinese immigrant communities in the Greater Toronto Area (Peizhong P. Wang, Memorial University of Newfoundland);
• healthy blood donors in most Canadian province (Darryl Leong, McMaster University); and
• Indigenous and First Nations populations living in Toronto, London and Thunder Bay, Ontario (Michael A. Rotondi, York University).