Quebec points to COVID-19 vaccine maker's rules as reason for slower than planned rollout

The plan was to burst out of the starting gate, but Quebec's vaccination plan has resembled more of a leisurely canter so far.

The province will miss its target of 56,000 vaccinations for COVID-19 by Jan. 1 but the government says there's a good reason for that: it is abiding by the manufacturer's requirement to hold back the second of a two-dose treatment.

As of Tuesday, the province had inoculated 22,500 people and had enough serum left to hit 27,000 by week's end. Quebec has said it hopes to inoculate 675,000 by April 1 but, based on the vaccinations to date, it will need to step up the pace considerably to get there.

"Just so everybody understands clearly ... we've received 55,000 doses to this point. Of those 55,000, there are 27,000 that must be held back. It's one of Pfizer's requirements," Health Minister Christian Dubé told a news conference Tuesday.

Pfizer Canada's director of corporate affairs, Christina Antoniou, said in an email "this was indeed our recommendation ... we consider it to be a safe approach for the points of use to continue storing a portion of the doses received, to ensure no delay in the second dose deployment."

The main reasoning was to employ a cautious approach as production ramps up. But Antoniou added "it is the responsibility of the provinces to determine how they will administer their immunization program."

Other provinces — including Ontario, British Columbia, Saskatchewan and Nova Scotia — have decided to use the reserve doses immediately so as to reach a larger portion of their population.

More shipments of the Pfizer-BioNTech vaccine are due to arrive in Quebec on Jan. 4 and Jan. 11. The province is also slated to receive the first shipments of the Moderna vaccine, which also involves an initial dose and a booster, this week.

Dubé said Quebec is studying the possibility of using its supply of the Pfizer-BioNTech vaccine more widely and expects to have Pfizer's assent to do so soon, saying "it's a matter of a week or two." 

On Wednesday, Dubé's department added a nuance, saying that because Pfizer is only confirming deliveries two weeks ahead of time "we have made the choice to conserve the second dose in order to ensure we are abiding by the [vaccination] intervals prescribed by the company."

Arruda, for his part, said his department has been examining clinical data to establish whether the immunity from a single dose of the vaccine, which various studies indicate is roughly 50 per cent after seven days, confers enough of a benefit to skirt the two-dose requirement.

"From the very beginning, we've been evaluating the possibility of using all our vaccine to protect the maximum number of people … we will not use what I would call a modified calendar if the data aren't sufficient," he said.

A recent University of Toronto study, obtained in draft form by CBC News, concludes that using single doses more widely rather than following the current Pfizer protocol of two doses within 21 days could inhibit new symptomatic infections by 34 to 42 per cent.

"If we could get more vaccines in the arms of long-term care residents and long-term care workers, this could potentially avert a lot of the potential infections in the coming weeks," said Ashleigh Tuite, an infectious disease epidemiologist and mathematical modeller at the university's Dalla Lana School of Public Health.

Though the vaccination campaign in Quebec is unfolding more ponderously than the government predicted, that doesn't mean it's going poorly, according to an epidemiologist at the Institut national de santé publique du Québec (INSPQ).

"Right now, the biggest problem is supply," said Dr. Gaston De Serres. "When we do have the doses, the administration of them is going fairly smoothly."

It's not like this is Quebec's first mass vaccination campaign. In 2009, the province was able to vaccinate 4.5 million people against the H1N1 avian influenza in the space of six weeks, De Serres said.

"In the first two weeks, supply was slow," he added. "We have the capacity to vaccinate 800,000 a week if there's enough supply."