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Expert warns pandemic modelling far from exact science as B.C. prepares to release new projections

Last Updated Apr 17, 2020 at 6:27 am PDT

This undated electron microscope image made available by the U.S. National Institutes of Health in February 2020 shows the Novel Coronavirus SARS-CoV-2, orange, emerging from the surface of cells, gray, cultured in the lab. Also known as 2019-nCoV, the virus causes COVID-19. THE CANADIAN PRESS/AP-NIAID-RML via AP
Summary

B.C. is set to release its latest COVID-19 projections, but an expert warns pandemic modelling isn't an exact science

Pandemic modelling expert explains projections can help give an idea of where an outbreak is trending

Projections can also give us a sense of what might happen when pandemic restrictions start to be relaxed, expert says

VICTORIA (NEWS 1130) – All eyes and ears will be on Victoria later this morning, with the province set to release its latest COVID-19 projections for the weeks and months ahead.

How long will it take to flatten the curve and start lifting lockdowns? That’s what everyone wants to know, and virus modelling gives an indication of when that might happen.

However, University of Toronto professor Dionne Aleman, a pandemic modelling expert, points out it’s not a precise science.

“It can’t give us an exact prediction, just because we don’t have exact numbers on exactly how many people are infected, or exactly how long they might stay infected, or exactly how people are transmitting the disease to the people around them,” she explains.

And even if they had all that information, Aleman notes a big wildcard is how people are actually behaving when it comes to physical distancing. There’s a lot of uncertainty that needs to be averaged over, she adds.

“We might say that 80 per cent of the population is physically distancing as they’re requested to, or maybe it’s 90 per cent. What about the people who are still working because their jobs are deemed essential?” Aleman explains.

While projections aren’t perfect, Aleman says that’s not the point of the models. She says they can get us into the ballpark when it comes to where the outbreak is trending, and what might happen when pandemic restrictions start to be relaxed.

“Because ultimately, disease spreads because we allow it to,” Aleman tells NEWS 1130. “The mechanism of disease spread is 100 per cent entirely driven by our own individual behaviours, and that’s just something that’s really difficult to predict.”

Aleman echoes the message that has been widely shared by all health authorities over the last few weeks: stay home as much as you can, and keep practising physical distancing.

“The better job you do with physical distancing, the sooner this will all be over and we can start the slow march back to normalcy,” she says.

On Thursday, the prime minister was asked why the number of deaths across Canada this week was larger than than the figure laid out in the government’s federal modelling. Justin Trudeau said models are not predictions, but rather projections of what might happen. He noted outbreaks at long term care facilities was worse than feared.

Last month, B.C.’s provincial health officer, Dr. Bonnie Henry, said hospitals in the province should be able to handle the rising number of cases of COVID-19 infections in the months ahead. However, she warned if public health guidelines were not followed, concerns about whether the healthcare system could face demands beyond capacity would grow.

So far, B.C. has not provided its death projections to the public.

-With files from Liza Yuzda