Provincial modelling says Quebec can cope with coronavirus variants if people follow the rules

·5 min read
A laboratory technologist in Vancouver holds a genome cartridge while working to sequence the genome of the SARS-CoV-2 virus last month.
A laboratory technologist in Vancouver holds a genome cartridge while working to sequence the genome of the SARS-CoV-2 virus last month.

(Ben Nelms/CBC - image credit)

March break may be a chance for a rest, but Quebecers shouldn't be lulled into falling asleep at the controls, says Public Security Minister Geneviève Guilbault.

To that end, Guilbault announced the province will dispatch police officers across Quebec — including cottage country, ski trails and snowmobile paths — to keep a wary eye on gatherings and uphold public health guidelines from Feb. 28 to March 7.

"Don't be surprised if you see our police officers," Guilbault said in Quebec City, "but it's just a matter to make sure that rules are respected, because it is very important so that number of cases of COVID, and hospitalizations, and deaths, and things like that keep on decreasing."

The measure falls well short of the roadblocks and highway checkpoints the government was musing about earlier this month, but it reinforces a part of Premier François Legault's Tuesday evening message the government clearly doesn't want anyone to overlook.

The provincial government is loosening the pandemic lockdown for spring break, but reserves the right to turn the screw once again if people don't play by the rules.

And there are good scientific reasons for taking a cautious approach.

The Canadian Press
The Canadian Press

The latest modelling from the Institut national de santé publique du Québec (INSPQ), suggests variant strains such as B117, first isolated in the United Kingdom, could well become the dominant, or at least most prevalent, form of novel coronavirus sometime next month.

The projections, which centre on greater Montreal for methodological reasons, sketch out a handful of different scenarios. They assume either strong adherence to strict public health rules (think: January) or moderate observance (ie., December) and either small-scale or large-scale importation of variants. Or combinations of both.

With large numbers of imported cases and a lackadaisical approach to personal contact and distancing, which is the worst-case scenario contemplated in the model, it's likely the number of new infections would skyrocket to 4,000 per day in April.

Hospitalizations and deaths would also increase, although the model's median trend line suggests they might not quite reach peak January levels, at least not by April.

In the other scenarios, the trend line either stabilizes, or continues to point gently downward.

That's partly a function of the relative success Quebec had in limiting variant clusters last month, and partly related to the ongoing vaccination of vulnerable populations, particularly the elderly in long-term care.

Submitted by Université Laval
Submitted by Université Laval

"The speed at which the variants spread will depend on how closely the population sticks to the guidelines," said Dr. Marc Brisson, an Université Laval modelling expert who led the exercise.

But as always with mathematical models, there are caveats.

The confidence intervals are highly variable, meaning there is a wide variation in possible outcomes. Put differently, the situation could go off the rails extremely quickly.

Brisson said it's not yet clear just how much importation of new variant strains happened over the December holiday period, which saw a boomlet in international travel and a general slacking off in terms of gatherings.

Also, the model assumes B117's severity is similar to the current dominant strain, and the existence of cross-immunity between strains. And it doesn't take the latest March break measures into account (although Brisson said "they are within our margin of error.")

On the first point, it appears several variants are highly-transmissible and may be more virulent.

A newly published study by researchers at Harvard proposes an answer as to why: it's not that B117 is inherently easier to catch, it's that people stay infected for longer and are thus contagious longer.

There are also concerns about so-called "immune escape" — mutations that thwart the immunity conferred either by having had COVID-19 or from vaccines.

"It shows how important it is that the government ramp up all their sequencing efforts and as well as other variant-specific screening approaches because these variants are definitely moving faster than the previous variants that we're used to," Dr. Benoit Barbeau, a virologist at the Université du Québec à Montréal, told CBC Quebec's Breakaway recently.

Quebec's data vacuum in terms of importation adds even more urgency to the ongoing effort to increase genomic sequencing and strain-specific screening capacity.

The difference between, say, 60 imported cases last December and 150 is profound in terms of the modelled impact. The variants, at least three of which have been detected in Quebec this year, will spread once they take root. The question is how quickly and how far.

In essence, Quebec is witnessing a race between variant spread and vaccines. But the results from the January confinement measures and early vaccination are encouraging.

According to Dr. Jocelyne Sauvé, the associate vice-president of the INSPQ, the province is in "a very favourable epidemiological situation right now."

She noted the number of outbreaks in CHSLDs and hospitals has dropped sharply as vaccines begin to take effect, and that more and more health-care workers are protected each week.

"What we're looking for is the speed of the spreading of the virus, if it's quick-spreading we could be faced with an increase of hospitalizations and deaths," she said. "If people are restrictive in whatever they do, in their social contacts, and if we have not imported too many variants we should be okay."