TORONTO (AP) – A national group of vaccine experts in Canada on Wednesday recommended that provinces extend the interval between two doses of a four-month-old COVID-19 to quickly inoculate more people amid a shortage of dose in Canada.
Several provinces said they would.
Prime Minister Justin Trudeau also expressed optimism that vaccination deadlines could be accelerated. And Health Canada, the country’s regulator, said emerging evidence suggests high effectiveness for several weeks after the first dose and noted the group’s recommendation in a tweet. But two senior health officials called it an experiment.
The current protocol is a three- to four-week interval between doses for Pfizer, Moderna, and AstraZeneca vaccines. Johnson & Johnson is a one-dose vaccine but has not yet been approved in Canada.
The National Vaccination Advisory Committee said extending the dose interval to four months would allow up to 80% of Canadians over the age of 16 to receive a single dose by the end of June simply with the expected supply of Pfizer-BioNTech vaccines and Modern. .
The second group would begin being administered in July as more shipments arrived, the group noted, noting that 55 million doses are expected to be delivered in July, August and September.
In comparison, the federal government previously said 38% of people would receive two doses by the end of June.
“I think they’re doing a reasonable calculation at a time of drug shortages,” said Dr. Andrew Morris, a professor of infectious diseases at the University of Toronto and medical director of the Sinai Health Network’s Antimicrobial Custody Program. University. “It simply came to our notice then. Let me ask you … A couple is given two shots. Do you give two to one or do you give one to each dose? It’s not obvious. “
The addition of the recently approved AstraZeneca vaccine to the country’s supply could mean that almost all Canadians would get their first shot within that timeframe.
“The efficacy of the first-dose vaccine will be closely monitored and the decision to delay the second dose will be continuously evaluated based on surveillance and efficacy data and post-implementation study designs,” the group wrote.
“Efficacy against worrying variants will also be closely monitored, and recommendations may need to be revised,” he said, adding that there is currently no evidence that a longer interval will affect the appearance of variants.
The updated guide applies to the three vaccines currently approved in Canada.
The committee’s recommendation came hours after the Atlantic coast province of Newfoundland and Labrador said it would extend the interval between the first and second dose to four months, and days after health officials in the coastal province of the Pacific, in British Columbia, announced that they would.
Manitoba and Quebec also said Wednesday they would delay second doses. And the Ontario Minister of Health said Ontario would quickly accelerate the launch of vaccines.
Earlier Wednesday, Trudeau said any change in public health guidelines regarding the timing of the two doses could affect the speed of vaccine launches in Canada, as well as the approval of more vaccines like Johnson and Johnson.
The provinces of Canada administer health care to the country, so it ultimately corresponds to the provinces.
Dr. Brad Wouters, executive vice president of science and research at the University Health Network, questioned the recommendation. “No one in the world has spent 4 months between doses. These are RNA vaccines that have never been used before. We should use evidence to make decisions. Canada is conducting a population experiment, “tweeted Wouters.
And Mona Nemer, the federal government’s chief scientific adviser, also said this week that the plan amounts to a “population-level experiment” and that the data provided so far by Moderna and Pfizer-BioNTech are based on a range three to four weeks between doses.
But Dr Bonnie Henry, British Columbia’s provincial health officer, said manufacturers structured their clinical trials in this way to get vaccines marketed as quickly as possible, but said research conducted in British Columbia, Quebec, Israel and the United Kingdom have shown that doses are highly effective first.
Dr. Supriya Sharma, chief medical adviser to Health Canada, the country’s regulator, told the Canadian Broadcasting Corporation at a time of limited supply that they are beginning to have more comfort with the idea of waiting for the second dose after seeing data from the real world strict interpretation of clinical trials.
“In the real world, we’re starting to see evidence from other countries that have delayed the second dose. ‘Oh, they still seem to have very good effectiveness.’ We have lab studies showing that the immune response is unlikely to fall,” he said. Sharma.