MONTREAL -- Quebec's supply of COVID-19 vaccines could take a hit if the province continues to follow a schedule that isn't recommended by its maker, provincial leaders suggested Monday.

On Monday, Premier Francois Legault said Ottawa is talking to the provincial government around how closely it will need to comply with the two-dose schedule laid out by Pfizer for the company's vaccine.

That schedule calls for a second dose of the vaccine to be given three weeks after the first dose. The Quebec government's plan calls for a modified schedule, with people receiving their second dose months after the first.

The government has claimed the modified schedule is part of an effort to vaccinate as many people as possible and that the first dose does grant a fair level of immunity, a claim that has been disputed by Pfizer.

"What the federal government has told us... is whether there's a real risk that a company like Pfizer might stop delivering doses because we're not respecting the [interval] between the two doses," said Legault.

"There, of course, we would comply, if it would lead to stopping procurement of the second dose," he said.

"But if we have the choice, and we want it to be the government of Quebec that makes that choice, we prefer vaccinating more people [with a first-dose-priority system]."

A Pfizer spokesperson said the company "cannot confirm that such consequences have been implied," but that "Pfizer has continued to encourage public health authorities across Canada to follow the Health Canada authorized dosing intervals."

A Health Canada spokesperson said an analysis of the benefits or drawbacks of a modified schedule is underway but that currently it is recommended "that Canadians receive both doses of the same vaccine, as close as possible to the authorized dosing regimen for each vaccine."

The number of vaccine doses available to Quebecers will increase substantially in the first week of February, according to federal data.

As of Jan. 7, the province had received 115,375 vaccine doses, with 82,875 of those being the Pfizer-BioNTech vaccine and 32,500 being made by Moderna. During the week of Jan. 11 to 17, the province will receive another 46,800 doses of Pfizer-BioNTech and 34,000 of Moderna.

The same amount of Pfizer-BioNTech is forecasted to arrive in Quebec each week until the end of the month. No data is available on how much, if any, Moderna vaccine will arrive in the province during that time.

In the first week of February, the number of Pfizer-BioNTech doses will jump to 82,875 per week, for each week of the month. The province will also receive 47,400 doses of Moderna in the first week of February and another 51,800 doses in the last week.

On Friday, 13,971 doses were administered, but that number went down in the following days. On Sunday, 8,400 vaccines were administered.

On Monday, Health Minister Christian Dube attributed the drop to a lack of supply, saying that this week, for example, the delivery schedule has Pfizer-BioNTech vaccines arriving on Tuesday, Wednesday and Thursday, while Moderna delivers on Wednesday and Thursday.

Legault said Quebec has fully ramped up its vaccinating capacity, meaning it's able to give out all the shots it receives almost instantly -- and the statistics bear him out.

"You've seen the numbers," Legault said. "We have administered 80 per cent of the vaccines that we received, the doses that we received. We are the province that has, up until now, [given out] the [greatest] percentage of what we've received."

According to the Quebec Health Ministry, 92,452 vaccinations, or 80 per cent of the the doses received thus far, have been given in the province since Dec. 14.

Only a week ago, Quebec was fourth among major provinces after Alberta, B.C. and Ontario, having given out just 37 per cent of the doses it had on hand. That proportion has now more than doubled.

Dube said 21,478 residents of the province's CHSLDs, or 53.7 per cent, have received a vaccine. 

According to the 2016 census, Quebec has a population of 8,164,361. 

--With files from CTV's Selena Ross