The committee that makes recommendations on the use of newly approved vaccines in Canada has changed its guidelines on the AstraZeneca-Oxford COVID-19 vaccine and is now recommending it be given to those over the age of 65.
The National Advisory Committee on Immunization (NACI) expanded its recommendations on Tuesday.
Earlier this month, the committee had recommended Canadians over 65 not receive an AstraZeneca-Oxford shot, while Health Canada, the regulator, had authorized it to be used in adults of all ages.
NACI’s initial recommendations were based largely on AstraZeneca-Oxford’s clinical trial data and didn’t examine real-world evidence past Dec. 7 — months before the effectiveness of the vaccine was fully realized in other countries for older age groups.
Dr. Caroline Quach-Thanh, chair of the committee, said the team updated its guidance based on recent real-world effectiveness studies — including new evidence from the United Kingdom, which has been administering the AstraZeneca vaccine to people 65 years of age and older.
“I think that people have to realize that if we’re flip-flopping, it’s just that we try to monitor the evidence,” she told a news conference.
Dr. Noni MacDonald, a professor of pediatrics at Dalhousie University and a global expert on vaccine hesitancy, said Canadians need to understand that science changes.
“The major point we need to keep making is advice will be adjusted as science evolves. This is what happened here — more evidence from real-world studies showed Oxford-AstraZeneca to be very effective in those over 65 years in decreasing hospitalization and deaths due to COVID-19,” she said.
“We recognize changing advice can cause anxiety but need to change as science evolves — that is a good thing.”
Quach-Thanh said the reasons behind the discrepancy between NACI and Health Canada could have been communicated better.
“I think the only thing that I would say would have been done differently is the communications support so that we would have been able to explain all this exactly as we’re doing today,” she said.
“I think the Public Health Agency of Canada has now recognized that this support was absolutely necessary and this is now put in place, could have been done earlier. But, you know, it’s the first pandemic of this size.”
mRNA vaccines should still be ‘prioritized:’ NACI
While NACI has expanded the age group for the AstraZeneca-Oxford dose, which is a viral vector vaccine, it is also recommending that mRNA vaccines, like Pfizer-BioNTech and Moderna, be prioritized for at-risk groups.
“While all available vaccines in Canada are safe and effective, NACI still recommends that in the context of limited vaccine supply, initial doses of mRNA vaccines should be prioritized for those at highest risk of severe illness and death and highest risk of exposure to COVID-19,” said a statement from the committee.
Dr. Isaac Bogoch, an infectious diseases physician and member of Ontario’s COVID-19 vaccine task force, said he’s worried that recommendation could also cause confusion and hesitancy.
“The recommendation basically suggests that people over the age of 65 should preferentially get an mRNA vaccine over this vaccine and I think it’s premature to compare vaccines head-to-head at this point in time for a variety of reasons,” he said.
“When we also put this in the context of Canada being in the midst of a public health emergency where we know all available vaccines will significantly reduce the risk of getting the infection … we wouldn’t certainly want anyone to delay getting a potentially lifesaving vaccine while waiting for another vaccine and there’s some concern that that could happen. And in fact we’re already hearing about stories of people delaying getting vaccine A for vaccine B.”