Canadians should get used to the “new normal” of strict physical distancing followed by a year, or more, of continued vigilance as the country’s most optimistic scenarios for weathering the COVID-19 pandemic show that the first wave of the virus could taper out in the summer.
“Our health care systems across the country are coping for the time being. But we’re at a fork in the road," Prime Minister Justin Trudeau said Thursday after officials released nationwide models for the pandemic. “The best possible outcome is no easy path for any of us.”
The bottom line: “This will be the new normal until a vaccine is developed" and that “could be a very long way off.”
Even with restrictive policies, the models show between 1 per cent and 10 per cent of the population could become infected with COVID-19 in the first wave of the pandemic, which could result in between 4,400 and 44,000 deaths. That means policies already in place, which have most Canadians staying home and many businesses shuttered or working at partial capacity, continuing into the summer.
Experts say the most hopeful models are likely optimistic and will require the country to massively ramp up testing and contact tracing in order to avoid a second surge when governments start to ease off the most restrictive measures.
The federal numbers come from dynamical models, which are computer simulations based on various assumptions about the characteristics of the disease and public behaviour over time. Rather than predict what will happen, they reveal what could happen and what factors most influence the spread of the disease.
At a technical briefing, Canada’s Chief Public Health Officer, Theresa Tam, and her deputy, Howard Njoo, outlined three possible scenarios facing Canada over the next year.
The scenario with the strongest epidemic controls, such as a high degree of physical distancing, testing and contact tracing, would have an upper limit infection rate of 10 per cent. Under that best-case scenario, Dr. Tam said the health care system starts to be “very pressured” once the infection rate hits 2.5 per cent and so officials are setting the “ambitious goal” of a 1-per-cent infection rate.
But Dr. Tam said it’s too early to say whether the country is on track for that goal and what the most likely scenario currently is. She also stressed that the models are estimates, subject to change.
Officials released the most detail for scenarios with infection rates of 2.5 per cent and 5 per cent. For example, in those scenarios, between 73,000 and 146,000 people could be sent to hospital.
Zulfiqar Bhutta, director of research at the Centre for Global Child Health at the Hospital for Sick Children in Toronto, said that the figures released by Ottawa are “reasonably representative” of the state of COVID-19 in Canada. However, he said focusing on the scenario in which no more than 5 per cent of Canada’s population is infected over the course of the pandemic “presents a somewhat overoptimistic picture.”
Dr. Bhutta said that it would be helpful for federal experts to add more nuance to the picture, including a better accounting of the differences between provinces and a closer look at outbreak hot spots.
If no restrictions were put in place, the models show between 70 per cent and 80 per cent of people could become infected and more than 300,000 people could die. A middle-of-the-road scenario could lead to an infection rate of 25 per cent to 50 per cent and more than 100,000 deaths.
Dr. Tam said it is “too early to tell” when the pandemic will peak in different parts of the country, because no region is yet on the downward slope of its infection curve.
She added that since at least half of all cases will come after the initial peak, some restrictions will need to stay in place to ensure the epidemic does not “reignite."
Beate Sander, a scientist with the University Health Network in Toronto, said in order to successfully shift out of physical distancing, Canada will need to massively ramp up other strategies, including much more testing, as well as efficient contact tracing and isolation of infected individuals to prevent a rapid resurgence of the virus.
“That’s the biggest fear,” Dr. Sander said.
Last week, Mr. Trudeau was pressed to be more forthcoming with the models. The Prime Minister said he was waiting for more provinces to release their own models, which the majority have now done. He also warned about the large uncertainties that make current projections about COVID-19 tentative at best.
Those uncertainties were underscored Wednesday in the results of a survey of 4,200 Canadians, by the Angus Reid Institute. Based on self-reported symptoms, the survey estimates 147,900 households have already experienced infections of the new coronavirus – a number far in excess of official case counts derived from testing.
A large fraction of those unreported cases would be mild or asymptomatic, something that has thwarted the efforts of modellers to better reflect the true extent of the virus in Canada.
Dr. Bhutta said federal officials can still take this into account when presenting their numbers to the public and changing estimates is “perfectly acceptable.”
“That is precisely why the public health folks should work closely with academic researchers in developing and regularly updating assumptions and projections," he said. “That has been both slow and variable in Canada and even the release today is weeks late."
Nicholas Ogden, a senior research scientist with the Public Health Agency of Canada, said one of the challenges is getting enough data, including about the transmission of the virus in Canada, to anchor and test the validity of the projections.
"It’s a very inexact science and we’re clearly wanting to learn from what is actually happening,” Dr. Ogden said.
Editor’s note: (April 17, 2020): An earlier version of this article misspelled Dr. Bhutta's first name.
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