Canada’s National Advisory Committee on Immunization (NACI) is recommending provinces and territories extend the time between first and second COVID-19 vaccine doses to four months amid vaccine shortages.
In new guidlines posted on the NACI website on Wednesday, the committee said “current evidence suggests high vaccine effectiveness against symptomatic disease and hospitalization for several weeks after the first dose, including among older populations.”
NACI said due to limited supply of COVID-19 vaccines, “jurisdictions should maximize the number of individuals benefiting from the first dose of vaccine by extending the interval for the second dose of vaccine to four months.”
“Extending the dose interval to four months allows NACI to create opportunities for protection of the entire adult population within a short timeframe,” the committee said. “This will not only achieve protection of the adult population, but will also contribute to health equity.”
According to NACI, approximately 80 per cent of the eligible population could be offered a dose of one of the approved mRNA vaccines by the end of June if jurisdictions implement a four-month interval between shots this month.
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While the NACI releases recommendations, it is ultimately up to the provinces to determine how they will administer the COVID-19 vaccines.
A number of provinces including British Columbia, Newfoundland and Labrador and Manitoba have already decided they will be extending the interval between COVID-19 vaccine doses.
Speaking at a press conference earlier on Wednesday, Prime Minister Justin Trudeau said the federal government is monitoring the vaccine rollout approaches across Canada.
“We’re paying for the vaccines, we’re bringing them in and then we’re working with, obviously, public health experts, the National Advisory Council on Immunization, (and) working with provinces and chief medical officers across the country in order to deliver those vaccines to Canadians in the most rapid and most effective way to keep people safe to get through this pandemic quickly,” he said.
Asked whether the timeline to get all Canadians vaccinated could change, Trudeau said we are “seeing some of the science shift,” adding that “some proposals put forward, which are very, very interesting, which could result in rapider timelines.”
“But every step of the way, we’re going to be informed by the experts, by science, by the recommendations on the best way to protect Canadians, particularly vulnerable Canadians, and the best way to get through this as quickly as possible,” he said.
‘Unchartered territory’
In a previous interview with Global News, Colin Furness, an epidemiologist with the University of Toronto, said veering from the recommended timeframes could be “dangerous” and “risky.”
“When the vaccines were validated or tested, they were tested according to a certain schedule,” he said. “When you lengthen it, you go into uncharted territory.”
Furness said changing the timeline could impact the vaccine’s effectiveness.
“It could be the same, (or) the effectiveness could be lower — that is, your body might actually start to shut down its immune response and so it wouldn’t have the same combined effect,” he said. “Or it’s possible that waiting will actually make the vaccines even more effective, that could happen, too.”
According to Furness, all options are possible until the vaccine’s long-term effects can be properly studied.
Currently, all three vaccines approved for use in Canada require two doses to be administered.
Health Canada approved vaccines from Pfizer-BioNTech and Moderna in December, and a candidate from AstraZeneca-Oxford last week.
However, Canada has fallen considerably behind even its closest allies when it comes to COVID-19 vaccine rollout.
By Wednesday evening 2,072,757 COVID-19 vaccines had been administered in Canada, meaning approximately 2.78 per cent of the country’s population has been inoculated.
In comparison, the United States has fully vaccinated 7.9 per cent of its population, according to a tally from Johns Hopkins University.
The federal government has maintained, though, that all Canadians who want a COVID-19 vaccine will have access to one by the end of September.
-With files from Global News’ Rachael D’Amore and Emerald Bensadoun