QUEBEC CITY – Quebec public health officials said Thursday that provincial advisers have recommended an extended COVID-19 vaccination program of up to 90 days between the first and second dose, more than double what a committee recommended national advisor a day before.
“In our context, this is the best strategy,” Health Minister Christian Dubé said at a news conference Thursday on the progress of vaccination in Quebec.
Quebec announced in late December that it would delay the second doses or “booster shots” of the vaccine, but the province had not said until Thursday what kind of delay it was considering.
Provincial officials say the second dose should arrive between 42 and 90 days after the first.
This schedule would allow the province to administer the vaccine to more people who would otherwise have to wait for the first dose, health officials said.
A 90-day delay is much longer than recommended by Pfizer (21 days for your vaccine), Modern (28 days for your vaccine) and federal public health advisers on their recommendation on Wednesday (up to 42 days). for both) vaccines).
However, this national advisory group, called NACI, said Thursday that the provinces have some leeway to make their own decisions and that they do not oppose Quebec’s 90-day calendar.
Canada’s Deputy Director General of Public Health, Dr. Howard Njoo, said the “exceptional circumstances” of certain provinces may mean they need to deviate from federal recommendations.
“It’s kind of the interaction between the real epidemiology, on the ground, the fact that there’s obviously an increase in the rate of cases, hospitalizations,” Njoo said, and the guidelines on the vaccine.
EXTENSION BASED ON EXPERIENCE, NOT DATA, SAYS QUEBEC
So why is the province talking about 90 days?
The advisor to the Ministry of Health, Dr. Richard Massé said Quebec experts believe immunity is likely to last more than 42 days, as recommended by the NACI group, but clinical trials have not extended beyond that.
Instead, they depend on past experience with other vaccines.
“What we have is the experience of working with a lot of vaccines,” Massé said. “Immunity is not something that is turned on or off.”
Although the Quebec Ministry of Health has said a single dose can provide up to 90% effectiveness against the virus, Pfizer says a single dose is only effective with 52.4%.
Massé told reporters that the discrepancy comes from different and more specific analyzes of Pfizer trial data.
He said Pfizer, when studying the issue, had included people who had received the first dose but had not had time to build up immunity.
“It takes 12 to 14 days to have immunity,” Massé said. “If you count people who have the disease two, three, five days after receiving the vaccine, it’s not really a failure of vaccination because immunity [hasn’t been built up]. “
An expert told CTV News this week that there are large variations in effectiveness estimates due to the small sample size of people who only received the first shot at the Pfizer trial. This expert, Dr. Donald Vinh, said that in his opinion, the effectiveness is likely to be in the range of 60 to 69%.
In a statement to CTV News, Pfizer Canada spokeswoman Christina Antoniou reiterated previous claims that Pfizer has not evaluated the effectiveness of its vaccine in alternative dosing programs.
“There is no data to show that protection after the first dose is maintained after 21 days,” he said.
“We recognize that recommendations on alternative dosing intervals are up to health authorities and may include the adaptation of public health recommendations in response to changing circumstances during a pandemic,” he wrote.
But for Pfizer, “as a biopharmaceutical company working in a highly regulated industry, our position is based on the label and indication agreed with Health Canada and reported by the data from our Phase 3 study.”
Minister Dubé said the province has been talking to Pfizer. On January 5, Pfizer told CTV News that Quebec had not informed the company before deciding to delay the second dose.
“We’ve had conversations with Pfizer,” Dube said, “to let them know why we made those decisions.”
Earlier this week, Prime Minister François Legault said that in discussions with the federal government, the province learned that there may be a risk of losing Quebec’s vaccine supply if Pfizer is not satisfied with its regime. dosage.
On Thursday, the Pfizer statement said that “the company remains[s] committed to our ongoing dialogue with regulators, health authorities and governments, and to our continued efforts to share data to help inform any public health decision aimed at defeating this devastating pandemic. “
Both Massé and Dubé said they expect an increase in supply, as they would favor a shorter delay before the second dose if vaccine deliveries in the province increase.
“Saving lives is a moral imperative,” Dubé said.
“The more doses we have, the more we can reduce the time between the first and second dose.”
NEXT STEPS FOR QUEBEC VACCINATION
With about 65% of CHSLD residents already receiving a first dose, Dubé said Quebec will begin vaccinating residents of nursing homes (APRs) on January 25th.
He said that with an extended schedule between the first and second dose, the province may also consider vaccinating the general population in general sooner.
With new vaccine shipments arriving in the province this week, Dubé said 115,000 people have now been vaccinated.
In total, the province has so far received 162,000 doses. Dubé says Quebec is on track to increase that total to 250,000 in February.
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Will delaying the second dose of the vaccine 90 days work? Dr. Caroline Quach is an epidemiologist and head of the Infection Prevention and Control Unit at Saint-Justine Hospital, the National Vaccine Advisory Committee.
–With Kelly Greig files from CTV