OTTAWA — Canada seemed to be off to a quick start. Its regulator had approved a coronavirus vaccine codeveloped by Pfizer just ahead of the United States, and national newscasts were soon filled with images of people getting their first injections.

But the hopes raised by the vaccination launch in December — buoyed, too, by news that Canada had ordered doses equal to 10 times its population — have soured. Production issues at Pfizer and Moderna, makers of the only two vaccines currently approved in Canada, have led to reduced shipments — including some weeks in which no vaccine has arrived at all.

But while the disruptions have become the talk of the nation, more fundamental factors involving Canada’s strategic decisions and its production realities have always meant that the launch of vaccinations would be more of a test run than a full-on rollout.

Even if Canada gets back on schedule, this nation of 37.5 million people is expected to receive just six million doses by the end of next month. To date, only about 1.5 million people have been injected.

Updates of a global ranking of vaccinations now receive nearly as much attention as hockey scores in the Canadian media. As Britain and even the United States, despite its problems, continue to rise in the rankings, Canada has dropped well down the list, sandwiched this week between Bangladesh and Romania.

The nation’s vaccine anxiety has, according to polls, led to a drop in approval ratings for Prime Minister Justin Trudeau’s performance during the pandemic. Nearly 60 percent of Canadians think the country should be performing better or at least as well as other industrialized nations, one poll found.

It’s also prompted sometimes heated criticism from the Conservative opposition in Parliament and from several provincial premiers whose governments are responsible for sticking needles into arms.

“While the world is vaccinating by the millions, the government can only deliver a few thousand,” Erin O’Toole, the Conservative leader, said in Parliament on Tuesday. “Where is the plan to get vaccines into the arms of Canadians?”

Mr. Trudeau, while acknowledging the impatience, has tried to offer assurances.

“People are worried, people are tired of this pandemic,” he said at a news conference last week. “There’s a lot of anxiety, and there’s a lot of noise going on right now. That’s why I want to reassure Canadians that we are on track.”

Canada has not been alone. Short shipments of vaccines have also led to tensions in Europe and other parts of the world

The pressure on Mr. Trudeau may begin to ease. After slowing and briefly cutting off shipments to Canada while it modified a factory in Belgium to increase production, Pfizer sent its largest shipment of vaccine so far to Canada this week. Part of that shipment, however, was delayed by severe weather as it transited through the United States.

While the prime minister has said that Pfizer’s renewed deliveries will allow Canada to hit its target of six million doses by the end of March, that still means the overwhelming majority of Canadians will still be waiting, probably well into summer, for their shots.

Vaccine and infection control specialists say that Canada’s start was always going to be sluggish because of several key factors, notably its decision last year to spread its 414 million orders among seven different companies to reduce risk rather than bet on a single vaccine in exchange for early delivery. Only two of those companies have vaccines approved for use in Canada so far.

And Canada faces inherent disadvantages, too: primarily the lack of an established vaccine producer headquartered in the country and its relatively limited production capacity to make the vaccines developed by foreign companies.

Experts said that the short or delayed shipments so far should not have surprised anyone.

“There’s never been a vaccine rollout where there weren’t shortages because of issues around working the bugs out of the manufacturing,” said Dr. Scott Halperin, a professor of medicine at Dalhousie University in Halifax and the medical director of the Canadian Center for Vaccinology. “So anybody who didn’t anticipate that there’d be some hiccups in the manufacturing process just wasn’t aware of the past.”

Dr. David N. Fisman, a professor of epidemiology at the University of Toronto’s Dalla Lana School of Public Health, attributed the national hand-wringing to another factor.

“It looks more like we’ve gotten what we had been expecting, with occasional hiccups,” he said. “So I think most of the sound and fury really relates to just political point scoring. Is there anything the federal government realistically could have done to have received more vaccine earlier and magically stopped those hiccups?”

Doug Ford, Ontario’s conservative premier, proposed one answer, though its political viability has been questioned. During a news conference last month he urged President Biden to send Canada one million doses of vaccine from a Pfizer factory in Michigan that’s within driving distance of the international border.

“Our American friends, help us out,” said Mr. Ford, who has avoided criticizing Mr. Trudeau. “You have a new president, no more excuses.”

Under Canada’s system, the provinces are responsible for running health care systems, including performing vaccinations, while the federal government regulates vaccines and drugs and negotiates prices. With the pandemic, Mr. Trudeau also took on responsibility for buying the country’s vaccine stockpile.

Brian Pallister, the premier of Manitoba, broke with that program last week and announced that his province will spend 36 million Canadian dollars to buy vaccines from a small company in Calgary, Alberta, that switched from developing a vaccine for cancer to the coronavirus.

“I just want a Canadian home field advantage,” Mr. Pallister, said as he called on other premiers to join him in “building a Canadian-made solution, not just for today but for tomorrow.”

But vaccine from the Calgary company, Providence Therapeutics, won’t speed up inoculation rates any time soon. The company, which has asked Mr. Trudeau’s government for financial aid, began the first phase of human trials for its vaccine only in late January.

Assuming its vaccine is approved, Providence expects to begin production late this year or early next year — long after Mr. Trudeau’s September target to vaccinate all Canadians.

Because Canada has released little information about its vaccine contracts, Mahesh Nagarajan, a professor at the Sauder School of Business at the University of British Columbia in Vancouver, said it’s impossible to determine if anything could have been done to speed deliveries.

But Dr. Nagarajan said the country’s relatively small population and its lack of membership in a trade bloc like the European Union put it in a comparatively weak negotiating position.

“When production is done in other places and when resources are scarce, you cannot simply assume people are going to ship things out,” said Dr. Nagarajan, adding that provincial efficiency in administering vaccines will probably determine whether Mr. Trudeau’s September target can be met.

Dr. Fisman said he is optimistic that Canada “will be awash in vaccine supply by summer.” Until then, he had some advice for Canadians.

“Folks need to take a few deep breaths and get through March and April,” he said. “I think we’re actually in an OK place.”