Half of Manitobans may have contracted Omicron: Toronto researcher

Transmission of the Omicron coronavirus variant was more widespread in Manitoba than any other province over the past three months, says an infectious disease researcher.

Dr. Tara Moriarty also estimates Manitobans appear to be the least susceptible to Omicron infection

People line up outside the Thunderbird House COVID-19 test site in Winnipeg in October 2020. While official reporting numbers, based on PCR testing, say only about five per cent of the provincial population has contracted COVID-19 since Dec. 1, a Toronto infectious disease researcher estimates at least half of Manitobans have been infected since then. (Lyzaville Sale/CBC)

Omicron transmission was more widespread in Manitoba than any other province over the past three months, according to an infectious disease researcher who estimates at least half of Manitobans have contracted the highly contagious variant of the coronavirus that causes COVID-19.

In data made public on Wednesday, University of Toronto professor Tara Moriarty estimates somewhere between 51 and 82 per cent of Manitobans have contracted the Omicron variant since Dec. 1.

She estimated 21 to 27 per cent of Canadians overall were infected with Omicron.

"It looks like the numbers for Manitoba are very high at this point and it may be the highest percentage in Canada," she told CBC in an interview.

Officially reported numbers say about 64,000 Manitobans have contracted COVID-19 since Dec. 1. That's only five per cent of the provincial population.

Since late December, however, public health officials have said official case counts greatly underestimate the true number of COVID infections, partly because of limited testing.

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Moriarty said she devised her estimates by taking the number of reported COVID-19 deaths and cases in each province and deducing total infections based on factors such as the limitations on COVID testing and test-positivity rates.

She also pegged Manitoba as the province with the fewest people left susceptible to Omicron infection.

Moriarty estimated zero to 27 per cent of Manitobans who are 40 or older are now susceptible to Omicron. That's because most older Manitobans have three doses of a COVID-19 vaccine or have already been infected with the illness.

She estimated 46 to 48 per cent of Canadians aged 40 and up overall are no longer susceptible to the variant.

"It looks like a very large percentage of Manitoba has been infected with Omicron at this point, but I think it's very important people [know] there is uncertainty in that range," she said.

"I don't want people to think Omicron is completely over in Manitoba. The lower range of the estimate is quite important."

Future variants may require masking; lockdowns unlikely

Manitoba Public Health has determined the Omicron wave is receding in the province, based on indicators that include declining COVID-19 hospitalizations and deaths, Winnipeg wastewater monitoring and workplace absenteeism reports.

The province plans to eliminate most of its remaining pandemic restrictions next Tuesday, when the indoor mask mandate and mandatory isolation rule for COVID-positive patients is slated to end.

Dr. Brent Roussin, Manitoba's chief provincial public health officer, said he can see the possibility of mask mandates returning if a new variant sparks a new wave of COVID-19 infections.

But he said it would be challenging to ask "an exhausted population" to once again adhere to "very tight restrictions" after two years of the pandemic.

Roussin said he is not concerned too much about the Omicron BA.2 subvariant, which appears to be more contagious than the initial Omicron variant. The new strain does not appear to be more lethal, he said.

"The real concern is … what does the next variant look like? Is that a variant that's going to evade our immunity? Is it a variant that has … more severe outcomes?" he asked.

"That's where that that uncertainty is."


Bartley Kives

Senior reporter, CBC Manitoba

Bartley Kives joined CBC Manitoba in 2016. Prior to that, he spent three years at the Winnipeg Sun and 18 at the Winnipeg Free Press, writing about politics, music, food and outdoor recreation. He's the author of the Canadian bestseller A Daytripper's Guide to Manitoba: Exploring Canada's Undiscovered Province and co-author of both Stuck in the Middle: Dissenting Views of Winnipeg and Stuck In The Middle 2: Defining Views of Manitoba.