OTTAWA -- Prime Minister Justin Trudeau says he sees “the light at the end of the tunnel” of the ongoing COVID-19 pandemic, after seeing the news that Pfizer’s COVID-19 vaccine candidate may be substantially effective and ready for distribution in early 2021.

However, he is urging people to not let down their guards, because data that suggests the vaccine may be 90 per cent effective at preventing COVID-19 is preliminary, and it could still be several months before any vaccine candidates are ready for mass distribution.

“In Canada and around the world, scientists are working very hard and doing a great job. We hope to see vaccines landing in the early next year. But between now and that it's really, really important that we double down on our efforts. We need to make sure we are controlling the spread of COVID-19 in the coming months, so that when vaccines get here we will be able to act quickly to protect all Canadians,” Trudeau said during a press conference on Monday.

“To be very clear: if you catch COVID in the coming days and weeks, a vaccine won't help you or your family,” Trudeau said, adding that he’s eyeing the first three months of 2021 as the timeline for a first vaccine to be available.

As The Associated Press has reported, Pfizer said Monday that initial data suggests the vaccine may be 90 per cent effective in preventing recipients from contracting COVID-19, but the company is cautioning that the initial protection rate might change by the time the study ends.

Pfizer is working with German firm BioNTech on the vaccine. Doses were given to human test subjects in Germany in April and in the U.S. in May.

In August, Canada signed a deal for 20 million doses of Pfizer’s mRNA-based vaccine, and said it was negotiating with the company to include options in the contract for obtaining additional doses. It’s expected that, once a vaccine or vaccines are ready to be administered to Canadians, the initial supplies will be rationed and given to the highest risk populations such as seniors and health care workers.

One of the potentially complicating aspects of this vaccine is that it has to be stored at a much colder temperature than most vaccines.

“The logistical distribution of this vaccine candidate will require some very careful cooperation… We are already working on those necessary logistical supports, but obviously, compared to potential later vaccines that will be much more stable at room temperatures, the logistics on this first vaccine are likely to be more complex and slightly more limiting in terms of where we can get this candidate out to then some subsequent ones,” Trudeau said.

In an interview on CTV’s Power Play, Conservative health critic Michelle Rempel Garner said she wants to see more detail from the government about the adequacy of this and other vaccines in the works, as well as more information in terms of distribution.

“We have not seen any sort of plan from the government on this, and Parliament hasn't been able to scrutinize this. In turn, that means the provinces likely haven’t been able to do that either. They need to be involved in this,” she said.

Similarly, NDP health critic Don Davies said that while the development is good news, he has outstanding questions about the cost and accessibility of an eventual vaccine.

The federal government has been working on the logistical procurement and planning process for months, coordinating between the Public Health Agency of Canada, Public Services and Procurement Canada, as well as the provinces and territories.

The vaccine candidate is one of several Canada has signed deals to procure, pending successful trials that Health Canada certifies. Innovation Minister Navdeep Bains told reporters on Monday that, to date, Canada has secured access to more than 300 million doses from a range of companies including AstraZeneca and Moderna.

“We know that there is a certain amount of uncertainty as to which vaccines will land first, which vaccines will be most effective, which vaccines will be best suited to different segments of the population,” Trudeau said.

Putting this optimism in context, Trudeau said that, while he sees “the light at the end of the tunnel,” Canadians need to keep doing their part.

“We need to stay strong and hang in there a few more months, maybe more than that, but we can see it coming,” Trudeau said, encouraging people to keep up their mask-wearing, hand washing, and physical distancing.

“That's how we'll get through this winter, to spring and a summer that will be much better,” he said.