Quebec City – Quebec public health officials said Thursday that provincial councilors have recommended an extended COVID-19 vaccination program of up to 90 days between the first and second dose – more than twice as recommended by a national advisory committee with a day earlier.
“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 dose or “booster shots” of the vaccine, but the province did not say until Thursday what kind of delay it intended.
Provincial officials now say the second dose should come between 42 and 90 days after the first.
Such a program would allow the province to administer the vaccine to several 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 his vaccine), Moderna (28 days for his vaccine) and federal public health advisers in their recommendation on Wednesday (up to 42 days for both vaccines).
However, the national advisory group, called NACI, said Thursday that the provinces have room for maneuver to make their own decisions and do not oppose Quebec’s 90-day calendar.
The Deputy Director of Public Health of Canada, Dr. Howard Njoo, said that certain exceptional circumstances in certain provinces may mean that they must deviate from federal recommendations.
“It’s a kind of interaction between the real epidemiology, on the ground, that there’s an obviously increased rate of cases, hospitalizations,” Njoo said and the vaccine guidelines.
EXPERIENCE-BASED EXTENSION, NOT DATA, SAYS QUEBEC
So why is the province talking about 90 days?
The adviser to the Ministry of Health, Dr. Richard Massé, said that experts in Quebec believe that immunity is likely to last more than 42 days, as recommended by the NACI group, but clinical trials have not been extended.
What it is based on, instead, is 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 ‘turned off.'”
While the Quebec Ministry of Health said a single dose can provide up to about 90% effectiveness against the virus, Pfizer says a single dose is only 52.4% effective.
Massé told reporters that the discrepancy stems from the different and more specific analysis of Pfizer process data.
He said that Pfizer, when studying the problem, included people who had received the first dose but had not had time to accumulate immunity.
“It takes 12 to 14 days to get immunity,” Massé said. “If you count people with the disease two, three, five days after the vaccine, it’s not really a vaccination failure, because immunity [hasn’t been built up]. “
An expert told CTV News weekly that there are large variations in effectiveness estimates due to the small sample size of people who received only the first blow in the Pfizer trial. That expert, Dr. Donald Vinh, said that, in his opinion, the effectiveness is probably somewhere in the range of 60-69%.
In a statement to CTV News, Pfizer Canada spokeswoman Christina Antoniou reiterated previous statements that Pfizer has not evaluated the effectiveness of its vaccine in alternative dosing schemes.
“There is no evidence that protection after the first dose is sustained after 21 days,” she said.
We recognize that recommendations for alternative dosing intervals belong to health authorities and may include adapting public health recommendations in response to evolving circumstances during a pandemic, she wrote.
But for Pfizer, “as a biopharmaceutical company working in a highly regulated industry, our position is supported by the label and indication agreed with Health Canada and informed by the data in our Phase 3 study.”
Minister Dubé said the province had spoken to Pfizer. On January 5, Pfizer told CTV News that Quebec did not inform the company before deciding to postpone the second dose.
“We’ve been in talks with Pfizer,” Dube said, “to let them know why we’re making those decisions.”
Earlier this week, Prime Minister François Legault said that in talks with the federal government, the province had learned that there could be a risk of losing the vaccine in Quebec if Pfizer was not satisfied with its dosing regimen.
On Thursday, Pfizer’s statement said the company “remains[s] engaged in our ongoing dialogue with regulators, health authorities and governments and our ongoing data sharing efforts to help inform any public health decisions aimed at overcoming this devastating pandemic. “
Both Massé and Dubé said they hoped for an increase in supply, as it 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 shorter the time between the first and second doses.”
THE FOLLOWING STEPS FOR VACCATION IN QUEBEC
With about 65% of CHSLD residents already receiving a first dose, Dubé said Quebec will begin vaccinating residents in private nursing homes (APRs) on January 25th.
He said that with an extended program between the first and second dose, the province can also consider vaccinating the older general population earlier.
With new vaccine deliveries arriving in the province this week, Dubé said 115,000 people have been vaccinated now.
In total, the province has so far received 162,000 doses. Dubé says Quebec is about to increase that total to 250,000 in February.
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Is the delay of the second dose of vaccine by 90 days going to work? Dr. Caroline Quach is an epidemiologist and head of the infection prevention and control unit at Saint-Justine Hospital, on the National Immunization Advisory Committee.
– With files from Kelly Greig at CTV