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How prevalent are variants? A closer look at what — and where — they are in Canada

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There is growing concern that highly contagious new variants of COVID-19 are picking up steam in Canada.

As of Feb. 17, Canada has logged more than 570 confirmed cases of the so-called “Variants Of Concern” (VOC) across all ten provinces.

Read more: Is Canada headed for a third wave of COVID-19?

 

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Some provinces ease restrictions as variant concerns rise – Feb 16, 2021

But experts warn that the true number is likely much higher and that progress in curbing coronavirus infections seen in some provinces could quickly be reversed.

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“These variants have been smoldering in the background and gaining fuel,” Canada’s top doctor, Theresa Tam, said Tuesday.

“That now threatens to flare up in a new, rapidly spreading blaze.”

How prevalent are they?

Newfoundland and Labrador is a “testament” to how things can go from bad to worse with variants, Tam said.

Up until recently, the Atlantic province had gone weeks with no active COVID-19 cases at all. The introduction of variants changed that — quickly.

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As of Monday, the province has linked nearly 300 cases with the B.1.1.7 variant, which was first identified in the United Kingdom.

The variant is considered to be more transmissible, meaning cases can multiply quicker. Other variants, like B.1.351 first identified in South Africa, have raised concerns about the efficacy of approved vaccines and reinfection.

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“Predictably, this is the type of scenario where the more you look, the more you find,” said Dr. Isaac Bogoch, an infectious disease specialist based out of Toronto General Hospital.

“Our understanding of how prevalent these variants are, by province and in the country, is only just increasing.”

Genomic sequencing, which is needed to confirm those cases, has been scaled up in recent months.

Read more: COVID-19 variants could be spreading across Canada. Are labs doing enough to detect them?

Labs in Ontario and across Canada have been sampling those who test positive and sending that sample to public health agencies where it’s sequenced to determine if the infection is variant COVID-19 or “regular” “wild type” COVID-19.

“There’s always been surveillance, even before we knew about variants,” Alon Vaisman, an infection disease physician at the University Health Network in Toronto, told Global News in a previous interview.

“That’s now being ramped up, expanded.”

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Experts say sequencing is beginning to paint a clearer picture of how burdened Canada is with variants, but it’s likely not yet fully realized.

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In British Columbia, for example, only about 15 per cent of samples that test positive for COVID-19 in the province are being sequenced for variants. While there have been just about 60 variant cases detected at this point, the time between transmission and confirmation of a variant case is longer than normal, making it difficult to extrapolate the true burden.

“The numbers are all probably an underestimate,” Bogoch said.

Some provinces, like Ontario and Alberta, have seen daily cases of regular COVID-19 decrease as variant cases rise.

Provincial health officials estimate about seven per cent of screened cases are due to variants. Dr. Adalsteinn Brown, co-chair of Ontario’s science advisory group, said last week that variants account for five to 10 per cent of all cases total.

The province anticipates that the variant from the U.K. will become the dominant strain by March. That B.1.1.7 variant accounts for more than 200 cases as of Feb. 17.

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After weeks of reporting thousands of new virus cases per day, Alberta has seen dramatic improvements too. Daily case tallies now run within the 200s. But variants have become an acute problem.

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As of Feb. 16, there were 221 confirmed variant cases — 214 of those being that of B.1.1.7 variant and seven being the B.1.351 variant.

Dr. Deena Hinshaw, the province’s chief medical officer, has expressed increasing concern.

“Many of these cases are the results of close contacts that we have identified through robust contact tracing,” she said.

“I’m particularly concerned about the growing number of cases that are not linked to travel.”

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Where are they coming from?

Community spread is where the concerns intensify, Bogoch said.

Four provinces have evidence that the variants are spreading within communities, meaning there is no known travel link to some new cases.

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Initially, the criteria to sequence virus samples included recent travels from places like South Africa, the U.K. and Brazil, where the main VOCs were first found.

As more and more cases are linked to community transmission, that criteria will need to be expanded, said Vaisman.

“Of the hundred or thousand positive cases a day, not all of them have been or do get sequenced — now more of them have to be,” he said.

Read more: Coronavirus variants are spreading throughout Canada. Is it still safe to reopen?

Bogoch said there needs to be greater transparency from provinces as to where the variants are being acquired and where outbreaks related to the variants have been identified.

“Outbreak-related information, we need that, it’s helpful,” he said.

Caroline Colijn, a mathematician and epidemiologist with Simon Fraser University, produced a model in January that estimated a skyrocketing spring wave fuelled by the community spread of these more contagious variants.

Colijn said that the hope is community spread has “not yet been established.”

Delaying that burden hinges, in part, on vaccination, she told The Canadian Press.

But “there’s still a good chance that we can prevent — or at least really delay — large numbers of this high-transmission variant coming into Canada.”

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Click to play video 'Canada’s Dr. Tam says new coronavirus variants need rapid response' Canada’s Dr. Tam says new coronavirus variants need rapid response
Canada’s Dr. Tam says new coronavirus variants need rapid response – Feb 16, 2021

What should we do?

Public health experts have warned against complacency and that it is too risky to begin easing restrictions as variants continue to spread.

“Collectively, we cannot afford to take the brakes off,” said Tam.

But that’s exactly what many of Canada’s provinces are doing.

Ontario lifted its stay-at-home order for much of the province this week and reopened schools, including those in hard-hit regions like Toronto and Peel. In Alberta and Manitoba, gyms and restaurants have reopened with limited capacity.

By contrast, Saskatchewan, where the variant spread is minimal, opted on Feb. 16 to extend its public health measures for at least four more weeks.

Read more: COVID-19 variants leave less ‘room for error’ in loosening restrictions, experts say

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Experts say cautiousness is the right idea.

Bogoch said it’s clear provinces are trying to find a balance between public health and keeping economies afloat. There has been obvious progress in many hard-hit provinces, he said, but reopening en masse (i.e. schools and businesses simultaneously) will only “create more opportunities for the virus to be transmitted more broadly.”

“Governments need to be able to react quickly. This is not the time to sit on our hands.”

“You’ve got to stay two steps ahead of this virus and its variants. If there are any indications that your progress has stalled, you’ve got to pump the brakes, because this can spiral out of control really quickly.”

–With files from The Canadian Press and Global News’ Heather Yourex-West