Several public health experts say they’re confident that Canada’s current batches of AstraZeneca COVID-19 vaccines would still be safe and effective, despite having their expiry date extended by a month.
In a statement Saturday, Health Canada said the expiry date of two lots of the AstraZeneca vaccine has been extended from May 31 to July 1.
“The approval to extend the shelf life was supported by scientific evidence,” the statement reads. Health Canada had previously approved a six-month shelf-life for the shot.
However, the agency said on Thursday it received a submission from AstraZeneca that “included product stability and mathematical modelling data that demonstrated that the quality, safety and efficacy of the two lots would be maintained for an extra month, for a total of up to seven months.”
Health Canada said the extension will “ensure that provinces and territories are able to use up their existing inventory and provide Canadians access to much-needed doses of the vaccine.”
A Health Canada spokesperson told the Canadian Press that 49,000 doses of the vaccine across Canada were previously set to expire on Monday.
The news comes as provinces rushed to get needles into the arms of Canadians as the deadline fast approached.
But, is extending the expiry date of vaccines safe to do? Could this impact the efficacy of the shots?
Here’s what experts say.
Is it safe to extend the expiry date?
Asked if it was a good idea to extend the expiration date, Dr. Isaac Bogoch, an infectious diseases faculty member at the University of Toronto, said: “Quite frankly, yes.”
Bogoch said it’s “fantastic” if Health Canada and AstraZeneca deemed that the vaccine to be a “safe product,” and that it was safe to extend the expiration date by a month.
Dr. Zain Chagla, an infectious disease physician at St. Joseph’s Healthcare in Hamilton, said Canadians can be “pretty reassured” of the doses’ efficacy even if they were used past the expiry date.
“The best before date isn’t always the day that everything spoils, right, and I think that the vaccines are appropriate and safe,” said Chagla, likening the expiry date to an “arbitrary date” that the drug company thought would be reasonable to place.
Chagla also said that considering seems to be a fairly wide demand for a second dose of the vaccine, the remaining shots should be used up in the next one or two weeks.
According to the National Advisory Committee on Immunization (NACI) website, the AstraZeneca vaccine has demonstrated an average efficacy of approximately 62 per cent in those 18-64 years of age.
The committee said in adults 65 and older who have received one dose of the shot, “real-world observational data of vaccine effectiveness have shown a reduction in the risk of symptomatic disease and hospitalization.”
While Bogoch also stated that there shouldn’t be any concerns over the vaccines’ efficacy, he mentioned that there should “transparency” from Health Canada and AstraZeneca on how they came to the conclusion on extending the dates.
He said that more information would help “give people more confidence if they had some questions as to whether or not this was safe to do.”
“But I mean, in all fairness, I have faith in our health and regulatory bodies,” he said. “They’ve done a very good job steering us through this so far, and I think it’s totally reasonable.”
Vaccination in Canada
By Thursday, Health Canada said 26,142,532 vaccines had been delivered to the provinces and territories. Of those, 2,852,880 were AstraZeneca.
As of Saturday morning, Canada had administered a total of 22,809,939 COVID-19 vaccine doses.
So far, 55.62 per cent of Canadians have received at least one vaccine, while a total of 1,928,405 Canadians are fully vaccinated against the virus, according to COVID Tracker Canada.
— With files from the Canadian Press
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