TORONTO (AP) – A national panel of vaccine experts in Canada recommended on Wednesday that provinces extend the interval between the two doses of a COVID-19 injection to four months to quickly inoculate more people amid a dose shortage. in Canada.
Several provinces said they would do just that.
Prime Minister Justin Trudeau also expressed optimism that vaccination timelines could be sped up. And Health Canada, the country’s regulator, said emerging evidence suggests high effectiveness for several weeks after the first dose and noted the panel’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 of the Pfizer, Moderna, and AstraZeneca vaccines. Johnson & Johnson is a one-dose vaccine, but it has not yet been approved in Canada.
The National Advisory Committee on Immunization 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 and Moderna vaccines . .
Second doses would begin to be delivered in July as more shipments arrive, the panel said, noting that 55 million doses are expected to be delivered in July, August and September.
By comparison, the federal government previously said that 38% of people would receive two doses by the end of June.
“I think they are making a reasonable estimate at a time of drug shortage,” said Dr. Andrew Morris, professor of infectious diseases at the University of Toronto and medical director of the Antimicrobial Management Program at Sinai-University Health Network. . “It is the right decision in my mind. Let me ask … A couple is given two shots. Do you give two to one, or do you give one to each dose? It’s a no-brainer. “
The addition of the recently approved AstraZeneca vaccine to the country’s supply could mean that almost all Canadians would receive their first injection in that time frame.
“The efficacy of the first dose vaccine will be closely monitored and the decision to delay the second dose will be continually evaluated based on surveillance and efficacy data and post-implementation study designs,” the panel wrote.
“Efficacy against the variants of interest will also be closely monitored, and the recommendations may need to be reviewed,” he said, adding that there is currently no evidence that a longer interval affects the appearance of the variants.
The updated guidance applies to the three vaccines currently approved for use in Canada.
The committee’s recommendation came hours after the Atlantic Coastal Province of Newfoundland and Labrador said it will extend the interval between the first and second doses to four months, and days after health officials from the Pacific Coastal Province of Columbia British announced that they were doing it.
Manitoba and Quebec also said Wednesday they will delay second doses. And Ontario’s health minister said Ontario would quickly accelerate the launch of the vaccine.
Earlier Wednesday, Trudeau said that any change in public health guidance regarding the timing of the two doses could affect the speed of the vaccine launch in Canada, as well as the approval of more vaccines like Johnson and Johnson.
Canada’s provinces administer healthcare in the country, so it is ultimately up to the provinces.
Dr. Brad Wouters, executive vice president for science and research at University Health Network, questioned the recommendation. “No one in the world has gone 4 months between doses. These are RNA vaccines never used before. We should use the evidence to make decisions. Canada is conducting a population experiment, ”Wouters tweeted.
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 is based on a three-to-three interval four weeks. between doses.
But Dr. Bonnie Henry, British Columbia provincial health officer, said manufacturers structured their clinical trials that way to get vaccines to market as quickly as possible, but said research in British Columbia, Quebec, Israel and the UK has shown first doses to be very effective.
Dr. Supriya Sharma, chief medical advisor to Health Canada, the country’s regulator, told Canadian Broadcasting Corporation at a time of limited supply that they are beginning to feel more comfortable with the idea of waiting for the second dose after seeing data from the real world versus strict interpretation of clinical trials.
“In the real world, we’re starting to see evidence from other countries that have delayed that second dose, ‘Oh, it looks like they still have really good effectiveness.’ We have laboratory studies that show that the immune response is unlikely to decline, ”Sharma said.