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Modelling COVID-19 trends is an imperfect challenge: expert

Last Updated Oct 28, 2020 at 6:15 am MST

CALGARY – The number of COVID cases in Canada is climbing quickly and at least one expert says there’s reason to be concerned with the trend.

But predicting where case numbers headed is not as easy as punching in some data and coming up with a number.

It also requires predicting how many contacts are happening and how people interreact.

“You can’t look at any piece of it in isolation, we look at cases, the percentage of people being hospitalized,” explained Tyler Williamson, associate professor with the University of Calgary’s department of biostatistics.

“Anytime you try and predict human behaviour is a challenge.”

It gets even harder when that behaviour that you’re trying to predict has changed so much since the spring.

“Anybody that wants to go more than a few days, I think is maybe a bit naïve. What we see reflected in the cases is not the cases that got infected yesterday, with the time it takes to book, the time that it takes to get test results. Even if those are really, really efficient there’s some lag there.”

Other provinces are good comparators since we have the same health system and living conditions are similar but Williamson says it’s “foolish” for us to believe we’re doing better.

Take Winnipeg, for example. After seeing a relatively quiet summer, the city is seeing an explosion of cases.

And that’s one thing even short-term projections are starting to show–a worrying trend towards runaway growth not just in Winnipeg, but here in Calgary and other major Canadian cities.

“The average, which is probably a better indicator of what’s really happening continues to rise, the effective reproduction number gives us an idea of how many secondary infections are a result of the primary infection,” he said.

“We want people to not be infecting more people, we want that to be dying off and across the province it’s big. Like scary big. It has a good opportunity for huge, exponential growth”

And no one wants to go back to March and April levels of restrictions.

“Perhaps the Thanksgiving bump, we can turn it into a positive thing. If we learn from it and are smarter about our interactions, then maybe Christmas isn’t a forgone conclusion.”