TORONTO — Canadian officials are defending a decision to accept coronavirus vaccines from a program aimed primarily at helping low- and middle-income countries, saying that drawing doses from the Covax Facility was always part of Canada's strategy.

“Our government will never apologize for doing everything in our power to get Canadians vaccinated as quickly as possible,” Deputy Prime Minister Chrystia Freeland said this week. “We’re focused on getting Canadians vaccinated, while making sure the rest of the world is vaccinated, too.”

Her remarks Thursday came after the Covax Facility, a global effort to source and equitably distribute coronavirus vaccines, announced its first country-by-country projections. The estimate suggested Canada could receive 1.9 million doses of the AstraZeneca vaccine by summer.

The prospect that a country as wealthy as Canada, which has cut several deals directly with vaccine makers, seeking additional doses alongside low- and middle-income countries through Covax has added a new element to the debate about vaccine hoarding by the rich at the expense of the poor.

It has also created a headache for Prime Minister Justin Trudeau’s government, which already was under fire for a vaccine rollout that has lagged behind many of its peers.

“Perhaps this is about reassuring the public that we’re trying to be on track,” said Erica Di Ruggiero, a professor of global health at the University of Toronto. “However, it is concerning because … we need to share our vaccine allocation, and before we all started to roll out our vaccine programs, we had already secured among the highest number of doses per capita of any country.”

Against the pandemic, she said, the world is only “as strong as our weakest health link.”

“While this might be a short-term fix to escalate rollout here, in the long term, it may come back to bite us.”

About 190 countries have signed on to Covax, an initiative of the World Health Organization, the Center for Epidemic Preparedness Innovations and Gavi, the Vaccine Alliance. Leaders of the effort, which is intended to ensure that high-risk groups in every country are immunized, say they have secured 2 billion doses for 2021.

But progress has been disrupted by wealthy countries making advance purchase agreements with drug companies, reserving much of the projected 2021 supply long before it has been shipped. Estimates suggest that low-income countries might be left waiting until 2023 or 2024 to secure enough vaccine to achieve herd immunity, delaying their recovery and return to the global economy, and giving the virus more time to mutate.

The first tranche of vaccine distributed through Covax will include about 330 million doses of the Oxford AstraZeneca vaccine and 1.2 million doses of the Pfizer-BioNTech vaccine in the first half of this year, divided among 140 countries, the program estimates.

Canada invested about $345 million in Covax. Half of that money was used to secure doses for domestic use and half of it to support low- and middle-income countries.

But it is now the only Group of Seven country getting doses from Covax in the first round. Only two other wealthy nations — New Zealand and Singapore — are receiving Covax vaccines early. (Some countries, including fellow G-7 member Germany, have donated to Covax without signing up to secure doses from the program. The United States has thus far declined to participate.)

Trudeau has been caught between domestic pressure to vaccinate the population and international pressure to support poorer countries. In some ways, Canada has tried to have it both ways — securing a large number of potential doses for its population while also talking about sharing with the rest of the world.

The country entered into advance-purchase agreements with seven drugmakers, securing access to hundreds of millions of potential doses and options to purchase more.

If all seven vaccine candidates receive regulatory approval and Canada exercises all of its options, the country will have enough doses to vaccinate its population of 38 million several times over. But much of that supply has yet to materialize.

Canada has 80 million guaranteed doses of the two-dose vaccines offered by Pfizer and Moderna, enough to cover every Canadian who wants to be vaccinated. But the bulk of that allocation is not expected to arrive until later this year. Doses that were scheduled to arrive sooner have been subject to delays, upending provincial vaccination plans.

Trudeau says Canada remains on track to vaccinate every willing Canadian by the end of September. So far, the country has administered 2.65 doses per 100 people, according to Oxford University’s Our World in Data.

As a result, Trudeau has faced growing calls to get more doses into the country more quickly. A large headline on the front page of the Globe and Mail warned that “The country’s early vaccination rollout is collapsing.”

Canada also has tried to cast itself as a global leader on vaccine access.

Karina Gould, Canada’s international development minister, touted the country’s role in developing a mechanism for countries to donate or exchange doses. The goal, she said at a Covax news conference in December, is “not about slowing anyone down, but speeding everyone up.”

But when asked by The Washington Post later that month whether Canada would wait to share doses until every Canadian had been vaccinated, she said the question was “hypothetical” because the country didn’t have a “closet full of hidden vaccines.”

“It’s premature for us to say, ‘On this day, at this time, [when] this many people are vaccinated, that we have excess doses,’ ” Gould said, “because those doses don’t actually physically exist yet. So it’s a bit putting the cart before the horse.”

She said that if Canada has a surplus, those doses would be donated through the Covax mechanism.

Conservative Party leader Erin O’Toole told reporters on Wednesday that Canada’s dipping into its Covax supply is “demonstration that we have no plan.” Green Party leader Annamie Paul cast it as “a very low moment” for Canada and said it made her “feel ashamed” and “embarrassed.”

Andrea Taylor, assistant director of programs at Duke’s Global Health Innovation Center, said she was “not really surprised” that Canada was tapping into its Covax supply, given the difficulty it has had getting doses into the country. She said that although it is “frustrating” to see a wealthy country with several advance-purchase agreements dipping into Covax, the country is using the mechanism as intended.

“Countries do need this kind of pushback about whether they are doing enough to ensure [vaccine] equity because the flat answer is no. No rich country right now is doing enough … and we are about to fall off of a cliff from which I’m not sure we can return,” Taylor said. “But I feel like it’s a little bit rich to give Canada such a hard time when they’re clearly not outperforming anyone in terms of actual vaccines delivered or vaccines administered.”

The health agencies behind Covax have warned repeatedly of the dangers of vaccine nationalism but generally have stopped short of criticizing specific countries.

At a news conference Wednesday, Seth Berkley, chief executive of Gavi, was asked about the ethics of rich countries such as Canada accepting vaccines from Covax while also cutting deals directly with manufacturers. He was unusually direct in his response.

Berkley said Covax’s initial purpose was indeed “to get vaccine to poor countries” and to limit side deals between countries and drug companies.

To secure support and funding from wealthy nations, Covax pitched itself to wealthy nations as a sort of “insurance policy” to supplement other deals, he said. But rich countries taking doses makes it harder for Covax to deliver on its original mission.

“Does it help when countries that have a lot of bilateral deals don’t take doses?” he asked. “Of course.”