Here’s how coronavirus could spread in Ontario

Here’s how coronavirus could spread in Ontario


By now, we’ve all heard federal Health Minister Patty Hajdu’s announcement Wednesday that between 30 and 70 per cent of Canadians could become infected with the novel coronavirus.

But what would that actually look like, on the ground and in number terms, for Ontarians?

Researchers at the University of Toronto and the University of Guelph are using complex mathematical modelling to give us an idea of just that.

Assuming that COVID-19 starts to spread locally, the researchers have created a variety of scenarios modelling how the virus will behave with different health interventions over a two-year time frame.

“There’s no silver bullet for controlling COVID-19 transmission,” said Ashleigh Tuite, one of the researchers and an epidemiologist at the Dalla Lana School of Public Health at U of T. “To reduce transmission and protect those most at risk will require enhanced detection and contact tracing, but also social distancing measures. Having said that, we do have the capacity to change the course of the pandemic with the tools that we have in hand.”

In one scenario devised by the researchers in which very little is done to contain the spread of the virus, Ontario would see a total of just over six million infections after about 16 months. In that same scenario, a maximum of 126,563 infected people would die.

In another, where schools are closed for about 18 months, deaths could be limited to 10,706.

The research is timely given that the Ontario government announced Thursday afternoon that it would shut down all publicly funded schools for two weeks after the March Break to help stop the spread of the virus.

A third scenario that further reduces social contact limits deaths to 3,291.

Tuite said slowing down the spread will buy time for researchers to develop a vaccine or a treatment.

Here are the three different scenarios:

The do very little scenario

This scenario assumes that there is little intervention in Ontario to stop the spread of the virus, which means limited testing for COVID-19 and limited tracing of individuals who may have come in contact with a patient. Only one in 10 people would be quarantined before they become infectious to others.

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The close the schools scenario

This scenario includes everything in scenario one, plus assumes that anyone under age 25 is no longer at school and that they have reduced their social contact to 40 per cent of what it was. The results are based on this scenario lasting around 547 days, or about 18 months.

The shut it all down scenario

This outcome assumes mass social distancing for about 490 days, during which people avoid school and work and reduce their social contact to 40 per cent of what it was. It would still allow for contact with family members and an outing to a store once in a while.

Note: Models are based on data from published studies of cases in China, including a large study published in the China CDC Weekly, of diagnosed COVID-19 cases as of Feb. 11, 2020.

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