The inexact science involved in predicting the likely path of COVID

Data experts are cautioning already on-edge Canadians against taking Ontario’s dire predictions about COVID-19 deaths literally, even as the revelation of stark data coincided with more physical distancing measures and impassioned pleas by government and health officials to stay home.

In presenting the data Friday, the president and CEO of Public Health Ontario said staying home could be the difference between 6,000 deaths by April 30 or 1,600 deaths. Deaths could drop to 200 if further measures are brought in, said Dr. Peter Donnelly.

Officials also offered a glimpse at what might happen over the length of the outbreak, which could stretch from 18 months to two years, but cautioned those scenarios become less certain the further into the future they are set.

If Ontario had not enacted various interventions including school closures, up to 100,000 people would die from COVID19, said Donnelly. But with various public health measures, deaths could number between 3,000 and 15,000, he said.

Pandemic experts say such projections are not really meant to predict the future, but rather to provide a general guide for policy-makers and health-care systems grappling with a growing pandemic.

Ideally, the information should also assure average citizens that their individual actions can make a difference, said University of Toronto epidemiology professor Ashleigh Tuite.

“That’s really important feedback to share not just within government, but with the population at large because everybody has a really huge investment in this,” says Tuite, who has created her own projections for the spread of COVID-19.

“The answer may be it’s going to take longer than we thought. And although that’s not the desired answer, it’s a possible answer. Communicating that (is) going to be really critical, especially if we’re looking at longer time horizons.”

Prime Minister Justin Trudeau said on Saturday he’s seen a range of projections.

“We know the situation is serious,” Trudeau said. “What actually happens, depends on the choices we make every single day. We can change the predictions.”

Provincial health officials have urged the public to “bear down hard” on isolation measures meant to break the chain of COVID-19 transmission, pointing to best – and worstcase scenarios they say largely depend on compliance.