New coronavirus variant could dominate in Ontario by next month, model shows

There's a race underway by public health officials across Ontario to assess how much of the highly transmissible variant first reported in the United Kingdom is now in the community, in order to keep it at bay until widespread COVID-19 vaccinations get underway.

COVID-19 cases double in 10 to 15 days, rather than in 40 days with current strain

The Public Health Ontario laboratory in Toronto, where the province's first tests for COVID-19 were conducted. The lab is now assessing samples to see how prevalent new, more contagious strains of COVID-19 might be. (Craig Chivers/CBC)

New modelling suggests a highly-transmissible new variant of the coronavirus first reported in the United Kingdom could — in the worst-case scenario — become the dominant strain in Ontario as soon as late February, well before mass vaccinations are set to begin in April. 

The model was created by Troy Day, a member of the Ontario Modelling Consensus Table and a mathematician who focuses on mathematical biology at Queen's University in Kingston, Ont.

It's based on projections of how the new variant is spreading across the U.K.

"I didn't believe it, actually," said Day, who passed his model around to his colleagues to make sure the rate of acceleration of the new variant's spread wasn't a mistake.

The threat posed by the more contagious variant partly lies in the time it takes for the number of COVID-19 cases to double, between 10 and 15 days, far fewer than the estimated 40 days of the current coronavirus strain.

"[Cases are doubling] every month-and-a-half ... compare that to if they double every 10 days. You can start to see that that would be a really horrific situation," said Day. 

Queen's University mathematician Troy Day has come up with a model that's caused some alarm about how fast a new coronavirus strain, first observed in the United Kingdom, could spread in Ontario. (Submitted by Troy Day)

'It's going to be a race'

Doug Manuel, a member of the Ontario Science Advisory Table and a scientist at The Ottawa Hospital, said his reaction to the model fell "somewhere between worried and scared." 

The presence of the new variant in Ontario, Manuel said, could have an impact on lockdown measures, hospitalizations and deaths. 

"It's going to be a race," he said. "If it spreads quickly, then it's going to be difficult for us to feel comfortable opening up. If it spreads slowly and we can do vaccinations quickly, then we're going to be in much better shape." 

In a press conference on Friday, Dr. Barbara Yaffe, Ontario's Associate Chief Medical Officer of Health, acknowledged the threat.

"We're in a serious situation," she said. "We have had six cases identified in Ontario, and we're doing way more testing to look for it. There's probably more that we don't know about."

Dr. Barbara Yaffe, Ontario's associate chief medical officer of health, said Friday the new variant poses a threat to efforts to control COVID-19. (CBC)

Provincial labs are now scrambling to pinpoint exactly how much of the new strain exists right now in the community.

Day's model is based on estimations that variant strains cause up to 0.1 per cent of all current COVID-19 cases. Finding out the precise number has become a massive effort by public health officials and laboratories across the province.

 "[That's] very important for the public health response as well as public health control measures," said Samir Patel, deputy chief of microbiology at Public Health Ontario. 

The new variant doesn't exist in the 7,000 samples already sequenced by the provincial lab and its partner labs since last September. Now they're digging into samples collected since December, focusing on travel-associated COVID-19 cases and those from hotspots and sending them to the provincial lab for full-genetic screening — a process that can take up to 10 days.

Provided by Public Health Ontario, this image shows the results of sequencing a COVID-19 sample, with the top graph showing the variant of the coronavirus first observed in the U.K. and the bottom graph showing the pre-existing strain. (Public Health Ontario)

Assessing the danger

Patel said scientists are also trying to understand how dangerous the variant is. 

For instance, it's not clear if it spreads faster among children, something that could affect back-to-school plans.

"There appears to be, based on the U.K. data, an increase number of cases in children," said Patel, noting that could be related to increased transmission in general among children rather than new behaviour by the virus.

"More data and more research needs to be done." 

Early findings do suggest vaccines remain effective on the new variant, he added.

More data is expected next week, but for now, Day says the early model has made public health officials cautious. 

"The thinking right now is, let's operate under the assumption that it's here," he said. "And let's try and do everything we can to slow it as much as possible."

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