When a vaccine for polio was announced in 1953, the CBC reported that in Canada, “the reaction was the same as at the end of a terrible war.” The 13,109 Canadians the Covid-19 has killed, the hundreds of thousands it has made ill and the economic turmoil it has brought to the nation also seem like the toll of a battle. The vaccine approved this week by Canada also seemed like if not an armistice, a turning point. The first shipment of the vaccine created by the American company Pfizer and a German firm, BioNTech, is likely to be still in transit this weekend, and the first inoculations could come as early as Tuesday. The initial quantities will be small compared with the millions of doses expected to arrive in the new year, making the first doses more an appetizer than a rollout.

[Read: Canada Approves Vaccine and Could Start Shots Next Week]

Surrounding everything related to the vaccine, of course, is who gets it when. Or, as a journalist put it to officials during one of the vaccine approval news conferences: “How are you going to make sure this isn’t like ‘The Hunger Games’ of vaccines?”

Who gets the shots first is a provincial decision. But a federal panel has come up with a list of recommendations for choosing the first recipients, a list of candidates that officials boil down to four groups: people over the age of 80; residents of long-term-care homes, a group that has accounted for 71 percent of deaths to date, and the workers who serve them; health care workers; and Indigenous communities.

For the first few thousand doses that are on the way, plans vary by province. Quebec will focus on long-term-care homes, while Saskatchewan will first inject health care workers.

In the three territories — the Northwest Territories, Nunavut and Yukon — no one will get the Pfizer-BioNTech vaccine in the near future. Instead, the governments in the Far North have decided to wait for the vaccine from Moderna, which is nearing approval and will be easier to handle, said Dr. Howard Njoo, the country’s deputy chief public health officer. It doesn’t require the ultralow temperatures that the Pfizer-BioNTech vaccine does.

Children will also not get the Pfizer-BioNTech vaccine immediately. It is approved only for use in people 16 and older.

Dr. Njoo cautioned that the decision-making wouldn’t end after officials determined which groups would get it first. They may have to decide if it is practical to initially vaccinate only people who live in the cities that are hosting the 14 centers to which the vaccine will be delivered. Every province has at least one center, with two each in Ontario and Quebec, but there are none in rural areas.

“If you’re going to vaccinate health care workers, well, where do you start?” Dr. Njoo asked at a news conference this week. “Might it be easier, more feasible, to do it starting off at a facility in an urban setting? Not to say that health care workers who provide health care, direct health care, in a more remote or rural setting are not as important.”

Whatever choices provinces ultimately make, the broad plan is to vaccinate only people from the top-priority groups until the end of March. During that time, the federal government expects to receive four million doses from Pfizer and, assuming it’s approved, two million doses of Moderna’s vaccine. By that time, governments will have to figure out how to deal with the remaining 35 million Canadians.

It has been widely noted that both the Pfizer-BioNTech and the Moderna vaccines use radically new technology. My colleagues Jonathan Corum and Carl Zimmer have prepared definitive guides to understanding both.