Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs), including the N501Y mutation (i.e., alpha/B1.1.17, beta/B.1.351, and gamma/P.1 variants) and the delta/B.1.617 variant, are associated with increased risks for hospitalization, intensive care unit (ICU) admission, and death, according to a study published online Oct. 5 in CMAJ, the journal of the Canadian Medical Association.

David N. Fisman, M.D., M.P.H., and Ashleigh R. Tuite, Ph.D., M.P.H., from the Dalla Lana School of Public Health at the University of Toronto, created a retrospective cohort of people in Ontario who tested positive for SARS-CoV-2 and were screened for VOCs, with test dates between Feb. 7 and June 27, 2021. A total of 212,326 people were included in the cohort.

The researchers found that the adjusted elevation in risk associated with N501Y-positive variants was 52, 89, and 51 percent for hospitalization, ICU admission, and death, respectively, compared with non-VOC SARS-CoV-2 strains. With the delta variant, increased risk was more pronounced at 108, 235, and 133 percent for hospitalization, ICU admission, and death, respectively.

"Canada is battling a different pandemic from the one it faced in early 2020. The virus has become smarter and more dangerous, which means that we need to be smarter too," writes the author of an accompanying editorial. "Canada's governments can keep people safe by enacting policies that wisely combine all the measures that have been shown to be effective."

One author disclosed financial ties to the pharmaceutical industry.

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