Canada on Wednesday approved the Pfizer-BioNTech Covid-19 vaccine, days after Britain became the first country to greenlight and roll it out.

“Today’s authorization marks a critical milestone in our efforts to bring Covid-19 under control,” the government’s chief medical advisor Supriya Sharma told a news conference.

“The availability of vaccines will increase throughout the year (2021), providing every Canadian with the opportunity to be immunized,” she added, saying three other vaccine candidates — including one developed by US-based Moderna, which could be delivered later this month — were currently being evaluated.

The Pfizer-BioNTech vaccine had undergone a fast-tracked review while it was still in clinical trials, which concluded that it met “stringent safety, efficacy and quality requirements for use in Canada,” said the country’s health department, Health Canada.

Marc Berthiaume, director of Health Canada’s bureau of medical science, said its evaluation found “strong evidence that the benefits of the vaccine outweigh the risks.”

The regulator advised, however, that it should be used only in people 16 years of age and up, for now.

Prime Minister Justin Trudeau said on Monday that as many as 249,000 doses would be received in December, with the first shipments to 14 sites across Canada arriving as early as next week and people receiving shots a day or two later.

Health care workers and vulnerable populations including the elderly are to be the first to receive it.

By September 2021, Trudeau said, most Canadians should be inoculated.

Thousands of Britons became the first in the Western world to receive the vaccine on Tuesday at the start of the biggest global vaccination drive in more than half a century.

The vaccine — which proved to be 95 percent effective in late-stage clinical trials — is administered in two doses, 21 days apart.

British health officials, however, warned on Wednesday that anyone with a history of significant allergic reactions should not get it right away, after two people suffered allergic reactions and needed treatment.

US giant Pfizer and its German partner BioNTech called Canada’s interim order for its emergency use “a historic moment in our collective fight against the Covid-19 pandemic” and “a major step towards returning to normalcy in Canada.”

They will continue providing data on its use for ongoing evaluation, according to Canada’s health department.

The federal government, meanwhile, has concluded pre-orders with several pharmaceutical companies — including AstraZeneca, Pfizer and BioNTech, Sanofi and GSK, Novavax, Johnson & Johnson, Medicago and Moderna — for 400 million doses, to ensure it eventually gets what it needs for its population of 38 million.