Asthma, cancer did not increase risk of testing COVID-19 positive, study shows

Cancer patients are at a higher risk of developing serious illness from COVID-19, but surprisingly had a lower chance of testing positive for the respiratory disease during Canada’s first wave of the pandemic.

That’s according to a new study published in the Canadian Medical Association Journal (CMAJ) on Tuesday that looked at data among nearly 14.7 million people in Ontario between March and June last year.

Canadians who suffered from asthma and coronary heart disease were also at lower odds of a positive test result.

Inequity when it comes to testing and access to healthcare rather than biological factors contributed to this association, the study authors said.

“This is a very clear illustration of the inequities we know already to exist,” said Maria Sundaram, lead author of the study and an infectious disease epidemiologist at ICES, a non-profit research institute based in Toronto.

The data appears to be skewed and does not paint a true picture of the pandemic because not everyone has equal access to testing in the country, she told Global News.

“This inequity really could not only be preventing us from having a really good pandemic response, it also can harm the science,” Sundaram added.

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Older people, and those with dementia and kidney disease, had a higher chance of testing positive for COVID-19, the study showed.

In contrast, receiving the flu vaccine in the 2019-20 season was associated with a reduced likelihood of a positive test result.

“This is a group of people who are being tested more often, are familiar with the healthcare system, and perhaps have reduced the number of barriers to accessing care,” Sundaram said.

“So they are in a better position, basically, to make sure that their health is in a good spot and also to get tested if they are worried.”

Testing was less common in areas that had a high household density, higher proportion of visible minorities and recent immigrants compared to higher-income quintile neighbourhoods, Sundaram said.

Yet area-level social determinants of health, including household density, essential work status, lower educational attainment and recent immigration status, were related to an increased risk of testing positive for COVID-19, she said.

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The authors stressed the need to increase and redirect COVID-19 resources to high-risk communities.

“Our findings also suggest prioritizing COVID-19 vaccination strategies that reach communities and workplaces having the highest rates of cases,” the authors wrote.

Besides vaccinations, testing and contact tracing are considered important tools to curb the spread of COVID-19.

The federal government has procured tens of millions of rapid COVID-19 tests, but many have gone unused by the provinces.

At a news conference on Tuesday, Prime Minister Justin Trudeau said the feds have consistently reached out to provinces, municipalities, large employers and pharmacies to ensure they have access to rapid tests as an extra screening measure.

“The federal government has pulled out all the stops and we will continue to make sure that we’re doing everything we can to get through this as quickly as possible,” he said.