A pharmacist fills a syringe with a Moderna COVID-19 booster vaccine in Antwerp, Belgium, on Dec. 27, 2021.Virginia Mayo/The Associated Press
Health Canada has approved an updated version of Moderna’s COVID-19 vaccine, a decision that means some of the millions of mRNA shots Ottawa has ordered for this season should begin arriving within days.
The federal regulator announced the authorization on Tuesday. Health Canada has not yet approved a new formulation of Pfizer-BioNTech’s COVID-19 vaccine, but a decision on that shot is expected soon.
Both revamped vaccines represent an effort by regulators and vaccine makers to keep pace with the COVID virus, which continues to evolve, threatening the immunity that Canadians have acquired through past shots and infections.
The U.S. Food and Drug Administration approved both Moderna’s and Pfizer-BioNTech’s updated mRNA shots on Aug. 22. A week later, it green-lit a new version of Novavax’s protein subunit vaccine, a shot that is also under review by Health Canada.
Many provinces withdraw COVID-19 shots, leaving gap as new ones await approval
In Canada, meanwhile, COVID immunizations have not been available in most of the country since the end of August, when the Public Health Agency of Canada asked provinces and territories to withdraw old versions of the shots from the market before Health Canada could sign off on their replacements.
Health Canada has approved an updated version of Moderna’s COVID-19 vaccine, a decision that means some of the millions of mRNA shots Ottawa has ordered for the 2024 fall season should begin arriving within days.Supplied
Health Canada told The Globe and Mail earlier in September that new mRNA shots would begin arriving in provinces and territories “within days” of regulatory authorization. Spokesman André Gagnon also said by e-mail that the country would be receiving up to 19 million doses of mRNA vaccines for the 2024-25 respiratory virus season.
Last season, nearly 8.2 million doses of COVID vaccines were distributed across the country between September and June, Mr. Gagnon added. The vast majority were mRNA shots.
After the new formulations begin arriving, it will be up to provincial and territorial governments to decide when and where to offer them. Some jurisdictions have already signalled their intention to make COVID shots available alongside annual influenza vaccines as they did last year.
Ontario’s flu vaccine campaign to begin in early October
Ontario announced last week that it would begin providing flu shots to high-risk people, such as hospital staff and nursing-home residents, beginning early next month. The province’s Ministry of Health said last week that it would release more information about its COVID vaccination campaign once the new shots were approved.
Timelines are expected to be similar elsewhere in Canada.
New formulations of the Moderna and Pfizer-BioNTech shots use the same mRNA backbone as past versions, but target a recent descendent of Omicron called KP.2. The target is a close cousin of KP.3.1.1, the fast-moving variant that accounted for an estimated 67.5 per cent of COVID cases in Canada as of Sept. 8.
KP.3.1.1, a sublineage of the JN.1 strain, has two notable mutations, said Fiona Brinkman, a professor of genomics and bioinformatics at Simon Fraser University who monitors the evolution of the virus for the Coronavirus Variants Rapid Response Network, or CoVaRR-Net.
One mutation increases the virus’s ability to evade prior immunity. Another makes it more adept at binding to human cells. “Thankfully,” Dr. Brinkman added, new versions of the COVID vaccines “look pretty good against what is circulating right now.”
Canadian public-health authorities don’t track cases of COVID as closely as they did at the height of the pandemic, but other surveillance indicators suggest COVID levels rose over the summer.
Nationally, the share of lab-based COVID tests that came back positive in the week ending Sept. 7 reached 18.3 per cent, up from 4.8 per cent in late April. The Public Health Agency of Canada’s waste-water testing indicates COVID levels are moderate in most of Canada, although the agency reports data from so few collection sites in some provinces that it can be difficult to get a bead on COVID activity outside of major cities.
Fortunately, most Canadians have hybrid immunity from past infections and vaccinations that protects them from severe COVID illness, said Isaac Bogoch, an infectious-disease physician with the University Health Network in Toronto. “Despite a surge in cases this summer,” he said, “we aren’t seeing anything remotely close to the scenes that we saw earlier in the pandemic.”
Dr. Bogoch emphasized that COVID still takes a toll on senior citizens and immunocompromised people, such as transplant recipients and cancer patients. Unlike influenza, which all but disappears in the summer, COVID sends people to hospital in the hottest months of the year, and has yet to settle into a predictable seasonal pattern.