Canada has become the third country to approve the Pfizer/BioNTech Covid-19 vaccine, as it prepares to take delivery of the first shots as early as next week.

The companies will supply at least 20m doses — and up to 76m doses — to the country, which has recorded 429,035 cases and 12,867 deaths attributed to the virus since the pandemic began. Sean Marett, BioNTech’s chief business and commercial officer, said they would be ready to ship as soon as they received the “greenlight” to begin distribution.

Prime Minister Justin Trudeau has said that Canadians will begin getting vaccinated next week, with 249,000 doses due to arrive by the end of the year.

Initial supply of the Pfizer vaccine will be limited, with more vaccines becoming available in spring 2021, according to Supriya Sharma, chief medical adviser for Health Canada, the country’s federal health agency.

“Today’s authorisation marks a critical milestone in our efforts to bring Covid-19 under control, and the availability of vaccines will increase throughout the year providing every Canadian with the opportunity to be immunised,” Dr Sharma said.

The shot has been initially approved for people 16 years of age or older.

The approval in Canada comes a day before an advisory panel of the US Food and Drug Administration will meet to discuss whether to recommend that the Pfizer/BioNTech vaccine receive an emergency use authorisation. In a report published in advance of the meeting, the FDA confirmed that the vaccine has an efficacy rate of 95 per cent on average and begins to work within about 10 days of the first dose.

Health Canada had been reviewing the trial data on a rolling basis. BioNTech will hold the regulatory approval in Canada, while Pfizer Canada will hold commercialisation rights.

Cole Pinnow, president of Pfizer Canada, said it was a “historic moment” and a “major step towards returning to normalcy in Canada”.

Pfizer will initially ship the vaccine to 14 sites identified by provincial governments across Canada. Major General Dany Fortin, head of Canada’s distribution efforts, said authorities conducted a dry run this week. A rehearsal co-ordinated by a national operations centre will take place on Friday.

Howard Njoo, Canada’s deputy chief public health officer, said the government would announce more details on allocation of the vaccine in the coming days.

Canada is also evaluating vaccine approval requests from Moderna, AstraZeneca and Johnson & Johnson. Marc Berthiaume, director of the Bureau of Medical Sciences at Health Canada, said Moderna was the furthest along in Canada’s regulatory process, but there was no date set for a decision. In clinical trials, Moderna’s vaccine has shown similar effectiveness to the Pfizer/BioNTech vaccine.

Canada has estimated that there will be up to 6m doses of Pfizer and Moderna vaccines rolled out before the end of March, which would be enough to vaccinate 3m people. Both vaccines require two doses — an initial shot followed by a booster.

The UK and Bahrain are the other two nations to approve the Pfizer/BioNTech vaccine so far. The UK began administering the first doses of the vaccine on Tuesday.

The UK medical regulator on Wednesday cautioned that people with a significant history of allergies should not receive the vaccine, after two NHS staff experienced an adverse reaction.

Canadian health authorities have been in contact with their counterparts in the UK to gather more information, officials said.

Dr Sharma said Canada has advised that individuals not get vaccinated if they previously had allergic reactions to any of the Pfizer/BioNTech shot’s ingredients. Health officials would evaluate whether to broaden that recommendation to include people who had other severe allergies, she added.