QUEBEC CITY -- A federal public health advisory board has recommended delaying the second dose of coronavirus vaccines, within a certain timeframe -- a model similar to what Quebec is following and which has made many Quebecers nervous.

The National Advisory Committee on Immunization (NACI) says health systems should try to give the second dose of the COVID-19 vaccine within 42 days of the first.

But even NACI’s deadline, should Quebec choose to follow it, is coming up fast for some of Quebec's first recipients of the vaccine.

Residents of the Maimonides Geriatric Centre, many of whom got the Pfizer-BioNTech vaccine on Dec. 14, 2020, threatened to sue the province after they were told they wouldn’t be receiving a second dose on-schedule.

Under NACI’s recommendations, they would be due for a second dose on Jan. 25.

Under Pfizer’s schedule, which recommends a delay of 21 days, they would’ve been up for another dose on Jan. 4.

Moderna’s vaccine -- not the one administered at Maimonides in December -- has a slightly longer waiting period before the second dose, at 28 days.


Quebec says it’s delaying the second dose in favour of giving first doses to as many people as possible.

But after Pfizer warned that it does not condone Quebec’s plan, people were left feeling insecure.

In an interview with CTV News, NACI President Caroline Quach said people should consider the real-world requirements to get the virus under control.

“We made a recommendation that was off label,” she said.

“If you follow the manufacturer’s indication, you might have the most benefit for an individual person,” said Quach.

“But when you make a recommendation that is for public health, your goal is to be able to protect the largest number of Canadians [possible].”


Quach also referenced a controversial number in her interview with CTV, claiming that clinical trials have shown that a single dose can provide about 90 per cent efficacy against the virus. Similar numbers around 90 per cent have been given in the past couple of weeks by various Quebec health officials.

However, Pfizer insists that's far from accurate, saying its trial data shows the first dose alone is only 52 per cent effective.

Whatever the effiicacy of the first dose on its own, researchers also don’t yet know how long that efficacy will last without the second dose.

With Ottawa securing another 20 million doses of vaccines on Tuesday, there may be more options available to lawmakers to immunize the population.

“If we had plenty of vaccines, we would not be asking any questions,” said Quach. “But we don’t have enough [to vaccinate everyone yet].”  

 -- With files from the Canadian Press