As a number of international locations report an uptick in COVID-19 instances partly blamed on a extra contagious model of the Omicron variant, the query turns into whether or not Canada’s subsequent wave might be a surge or a ripple.
The confluence of easing COVID-19 protocols and the rise of BA.2, a sublineage of the Omicron variant, is complicating the epidemiological forecast for spring, specialists say.
Whereas most agree that Canada’s immunization charges ought to blunt the impacts of the so-called “stealth” subvariant, some fear that decreased public well being vigilance might clear a path for BA.2 to drive up infections and hospitalizations.
Canada’s chief public well being officer steered final week that the nation ought to be shielded from the worst of the COVID-19 resurgence that is roiling areas overseas, as a substitute predicting a spring “blip” as public well being measures are lifted.
Whereas proof means that BA.2 is extra transmissible than its Omicron predecessor, the subvariant is spreading at a comparatively sluggish price in Canada, stated Dr. Theresa Tam.
It would not seem to to trigger extra extreme sickness than different variants, she stated, however worldwide information suggests BA.2 targets individuals who aren’t protected by vaccination or earlier publicity to the Omicron variant.
Which means Canada’s excessive immunization uptake — with 81 per cent of the inhabitants thought-about absolutely vaccinated — ought to maintain hospitalizations at manageable ranges even when instances rise, stated Tam.
However Dr. Lynora Saxinger, an infectious illness specialist on the College of Alberta, warned that the dangers of BA.2 may very well be erratically distributed throughout Canada.
Omicron reinfection seems to be uncommon, Saxinger stated, so areas that have been hit arduous by the BA.1 surge could fare higher than these the place the variant hasn’t been circulating.
“I believe it will likely be very variable between even cities, communities and provinces, and total throughout the nation,” she stated. “In locations the place they have not had a whole lot of an infection not too long ago, I believe there is a little more threat that this extremely transmissible variant might make a much bigger wave.”
One other issue to contemplate is uptake of third vaccine doses, which do loads “heavy lifting” in defending towards extreme outcomes from Omicron an infection, stated Saxinger. Federal numbers counsel that roughly 46 per cent of the inhabitants has acquired a booster shot.
What’s much less clear to Saxinger is whether or not reimposing COVID-19 guidelines would do a lot to curb BA.2’s unfold, noting that the subvariant has gained steam in locations with strict public well being measures.
“I believe there is a vast enjoying subject in between giving up, which I do not assume is the precise reply, and performing some type of draconian lockdown on an early sign.”
Caroline Colijn, a mathematician and epidemiologist at Simon Fraser College, is not satisfied that BA.2 will register as only a “blip” in Canada’s COVID-19 trajectory.
The Canada 150 Analysis Chair in Arithmetic for Evolution, An infection and Public Well being stated her modelling means that Canada is effectively positioned to climate an uptick in transmission pushed by both BA.2 or stress-free COVID-19 restrictions independently, however the mixture of the 2 might trigger issues.
“We could be very resilient to an increase in transmission, and BA.2 will give us an increase in transmission. However decreasing our measures and eradicating our protections will even give us one other rise in transmission on the identical time,” Colijn stated.
“I believe we’re resilient to some enhance in transmission. However I believe we are going to most likely see a surge from these two will increase in transmission arriving on the identical time.”
Of specific concern to Colijn is how BA.2 might have an effect on those that are most weak to extreme COVID-19 outcomes, similar to people who find themselves older or immunocompromised.
These teams have been prioritized for early boosters in lots of components of the nation, Colijn famous, and so the immunity offered by these doses usually tend to have waned within the months since.
As many provinces have restricted entry to testing, Colijn stated, we could not have the info we have to measure to elevated COVID-19 transmission earlier than hospitalizations tick up, at which level, it’s going to be too late to comprise the scenario.
“I believe we ought to be going into this with our eyes open and watching fastidiously,” she stated.
This report by The Canadian Press was first printed March 22, 2022.