QUEBEC CITY – Public health officials in Quebec said on Thursday that provincial advisers have recommended an extended vaccination schedule for COVID-19 of up to 90 days between the first and second doses – more than double what a national advisory committee had recommended the day before.
“In our context, that is the best strategy,” said Health Minister Christian Dubé at a press conference on Thursday about vaccination progress in Quebec.
Quebec announced in late December that it would delay second doses or “booster shots” of the vaccine, but the province had only said on Thursday what kind of delay it had in mind.
Provincial officials now say the second dose should come between 42 and 90 days after the first.
With such a schedule, the county could give the vaccine to more people who would otherwise have to wait for their first dose, health officials said.
A 90-day delay is much longer than what Pfizer (21 days, for its vaccine), Moderna (28 days, for its vaccine), and federal public health advisers recommended in their Wednesday recommendation (up to 42 days for both vaccines).
However, that national advisory panel, called NACI, said on Thursday that provinces have some leeway to make their own decisions and that they are not opposed to Quebec’s 90-day timeline.
Canada’s Deputy Chief Public Health Officer, Dr. Howard Njoo said the “exceptional circumstances” of certain counties may mean they must deviate from federal recommendations.
“It’s kind of a trade-off between the actual epidemiology, on the ground, the fact that there’s clearly an increased number of cases, hospitalizations,” Njoo said, and the vaccine guidelines.
EXPANSION BASED ON ‘EXPERIENCE’, NO DATA, SAYS QUEBEC
So why is the province talking about 90 days?
Dr. Richard Massé, an adviser to the Department of Health, said Quebec experts believe it is likely that immunity will last longer than 42 days, as recommended by the NACI panel, but clinical trials have not progressed further.
What they rely on instead is previous experience with other vaccines.
“What we have is the experience of working with many vaccines,” said Massé. “Immunity is not something that is ‘on’ or ‘off’.”
While the Quebec Department of Health has said a single dose can provide up to about 90 percent efficacy against the virus, Pfizer says one dose is only 52.4 percent effective.
Massé told reporters that the discrepancy stems from a different and more specific analysis of Pfizer’s trial data.
He said that when studying the matter, Pfizer had included people who had received their first dose but had not had time to build up immunity.
“It takes 12 to 14 days to have immunity,” said Massé. “If you include people who get the disease two, three, five days after getting 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 wide differences in efficacy estimates because of the small sample size of people who only got the first admission in the Pfizer study. That expert, Dr. Donald Vinh, said the efficacy in his opinion is likely to be somewhere between 60 and 69 percent.
In a statement to CTV News, Pfizer Canada spokesperson Christina Antoniou reiterated earlier statements that Pfizer has not evaluated the efficacy of its vaccine based on alternative dosing schedules.
“There is no data to show that protection lasts after the first dose after 21 days,” she said.
“We recognize that recommendations on alternative dosing intervals rest with the health authorities and may include adapting public health recommendations in response to changing circumstances during a pandemic,” she wrote.
But for Pfizer, “as a biopharmaceutical company operating in a highly regulated industry, our position is supported by the label and indication agreed with Health Canada and based on data from our Phase 3 study.”
Minister Dubé said the county has spoken to Pfizer. On Jan. 5, Pfizer told CTV News that Quebec had not informed the company before deciding to delay the second dose.
“We had discussions with Pfizer,” said Dube, “to inform them why we made those decisions.”
Earlier this week, Prime Minister François Legault said the province had learned during talks with the federal government that there is a risk of Quebec’s vaccine stockpile being lost if Pfizer is not satisfied with its dosing regimen.
On Thursday, Pfizer’s statement said the company “will remain[s] committed to our ongoing dialogue with regulators, health authorities and governments, and to our ongoing efforts to share data to help inform public health decisions aimed at defeating this devastating pandemic. “
Both Massé and Dubé said they hope for a greater supply as they prefer a shorter delay before the second dose as vaccine deliveries increase in the province.
“Saving lives is a moral obligation,” said Dubé.
“The more doses we have, the more we can shorten the time between the first and second dose.”
NEXT STEPS FOR QUEBEC’S VACCINATION
Now that about 65 percent of CHSLD residents have already received a first dose, Dubé said Quebec will begin vaccinating residents of private senior housing (RPAs) on Jan. 25.
He said that with a long-term schedule between the first and second dose, the province may also consider vaccinating the general senior population earlier.
With new vaccine shipments arriving in the province this week, Dubé says 115,000 people have now been vaccinated.
In total, the province has received 162,000 doses to date. Dubé says Quebec is on track to increase that total to 250,000 by February.
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Will it work to delay the second dose of the vaccine for 90 days? Dr. Caroline Quach is an epidemiologist and heads the infection prevention and control unit at Saint-Justine Hospital, on the National Immunization Advisory Commission.
– With files from CTV’s Kelly Greig