A new peer-reviewed study focused on Manitoba confirms what many public health experts have believed for months — those who live in remote northern regions, survive on a low income or live in long-term care facilities are the most vulnerable to COVID-19.
The University of Manitoba-led study, published in the October issue of the journal The Lancet Regional Health: Americas, suggests that the people most at risk from the disease are more vulnerable because of inadequate testing, increased case numbers in close proximity and an elevated risk of severe outcomes.
The population-based study used data from all lab-confirmed cases of COVID-19 in Manitoba from March 2020 to May 2021. All of the data came from the clinical and administrative registries and databases of Manitoba Health, and looked at infections based on sex, neighbourhood average income and health region of residence.
One of the most jarring findings suggests that the risk of contracting COVID-19 for people in the lowest income bracket was 1.3 to six times the risk for those in the highest income bracket.
Income level also had a big impact on the severity of infections, the data suggests, with patients from lower income neighbourhoods more likely to end up in intensive care, for example.
That’s likely due to a combination of factors for lower-income people, including crowded housing and continuing to perform essential front-line work in close proximity to other people, the study says.
Another likely factor was barriers to health-care, including the remoteness of the north, a lack of local health-care infrastructure and systemic racism that disadvantages both Indigenous and migrant groups in Canada, it says.
Manitoba prioritized vaccines for adults living in First Nations communities in Stage 1 of its vaccine rollout plan. When the province began its age-based vaccine rollout in March, First Nations people became eligible at an age 20 years below that of the general population.
That was intended to “ensure the same level of risk experienced by First Nations people at younger ages is adequately addressed,” Dr. Marcia Anderson, who is part of the Manitoba First Nations Pandemic Co-ordination Team, said at a February news conference.
However, later in the summer, the province acknowledged a greater risk from COVID-19 among Black and Indigenous people and people of colour than white Manitobans.
Data at that time suggested that while the vaccination rollout was based primarily on age, COVID-19 disproportionately hurt minority groups due to other risk factors such as lower income levels, higher rates of overcrowded housing and jobs with more contact with the public.
Manitoba also prioritized people living in congregate living facilities like long-term care homes in its vaccine rollout because of increased risk of COVID-19, including severe outcomes like hospitalization and death.
That’s in line with the findings in the U of M study.
“Especially in the second wave, their risk was doubled for dying from the disease,” said lead author Christiaan Righolt, a researcher at the Vaccine and Drug Evaluation Centre at the U of M’s Rady Faculty of Health Sciences.
Their risk was higher because of their complex health needs and proximity to others, Righolt said.
Children can be asymptomatic carriers
Children under 12 are still not eligible for COVID-19 vaccines in Canada, and while Righolt said it’s unlikely children that age will develop severe outcomes, they might still spread the disease, even if they don’t show symptoms.
Across all of Manitoba’s health regions, children younger than 10 had the lowest rate of positive tests while showing symptoms but the highest rate of asymptomatic testing, the study says.
“Some children that are symptomatic might have other viruses that prompts them to be tested,” Righolt explained.
“We do know that children that have COVID-19 don’t have as many symptoms and are more often asymptomatic, and they also don’t face as many of the severe outcomes, such as hospitalization and death, but they can still carry the disease.”
Although the study is based on high-quality, population-based data from Manitoba Health, the authors acknowledge there may be some misclassification of COVID-19 cases, either because of false test results or data entry errors.
There are also likely more cases of COVID-19 that didn’t make it into provincial record because of high positivity and low testing rates in Manitoba’s Southern Health region, the study says.
Righolt says his team is doing followup studies looking at vaccine efficacy and the predictors of infections that occur in people who are fully vaccinated.
“These results, together with those future results, would hopefully guide us to know who remains most at risk,” Righolt said.
Knowing that could help “direct the public health resources to those that are most at risk,” he said.