With the Food and Drug Administration’s authorization of a coronavirus vaccine on Friday, the United States became the third highly developed Western country — after Britain and Canada — to approve such a shot, and is expected to start inoculating people within days.
But the three countries have very different health care systems. And they face different challenges in the race to get the vaccine to millions of people.
Here are some similarities and contrasts.
Is it the same vaccine?
For now, yes.
The first vaccine authorized by American regulators, and the first approved by their British and Canadian counterparts, is the one developed by the pharmaceutical giant Pfizer and a small company, BioNTech. It could gain European Union approval within weeks.
But several others are close behind, particularly a vaccine developed by Moderna and the National Institutes of Health, and another from AstraZeneca and the University of Oxford. It could well be that half a dozen or more vaccines are approved in the coming months.
So as 2021 unfolds, which shots (most of the inoculations would require two injections, weeks apart) someone gets could vary widely by country, depending on the speed of regulatory approvals, what deals governments have made to buy supplies and how much the vaccines cost. Even within a country, there could be differences based on how easy it is to distribute and use a particular vaccine.
The Pfizer-BioNTech and Moderna-N.I.H. vaccines are of a new type never used before; they require ultracold storage and are more expensive than the likely competitors. The Pfizer shot has to be kept especially cold, at minus 94 degrees Fahrenheit, which most health care facilities aren’t equipped to handle.
How centralized is the rollout?
In Britain, very. In the United States, not. In Canada, somewhere in between.
With a strong central government and a National Health Service that covers all of its people, Britain, which began giving the vaccine this week, is directing the process from London. The national government chose the 50 hospitals that would initially get the vaccine and made sure they were prepared; decided how much each one would receive; and drafted the rules determining in what order people would be eligible to get it.
The Trump administration has deferred much of the decision-making to the states. The federal government will have the vaccine distributed to each state based on population, not need, but some states have complained that they do not know enough about the arrangements.
It will be up to the states to decide how to divide the doses among hospitals, clinics and, ultimately, drugstores and doctors’ offices, but at first, at least, the vaccine will go to hospitals with ultracold storage.
A committee advising the Centers for Disease Control and Prevention is drawing up a priority list, starting with medical workers. But that work is still underway, and the guidelines are nonbinding. States are expected to differ somewhat in their approach.
Like Britain, Canada has a universal health care system, but like the United States, it has a federal government. The Canadian health care system is decentralized, administered by the provinces and territories.
For vaccine distribution, the central government plans to work through those regional governments. Ottawa will play a large role in directing the process.
How many people will get it at first?
That remains a bit murky.
Canada had ordered enough of the Pfizer-BioNTech vaccine for all of its people, Britain enough for 30 percent and the United States enough for 15 percent.
But those numbers reflect deliveries that are expected to take months to complete, and Pfizer, like other companies, has hit snags in ramping up production. In addition, all three countries have made advance purchases from other companies, as well, so the pace of vaccine approval could significantly affect the speed of rollout.
That speed will also be affected by the need for vaccination sites to be equipped with the right freezers, the staff to prepare the shots, and enough syringes and protective gear.
The initial shipments are a small fraction of the pre-purchases — 800,000 doses to Britain and an expected 249,000 this month to Canada.
U.S. officials have said they hope to have 40 million doses of the vaccine by the end of the month, which may be optimistic. That would be enough to inoculate 20 million people.
Rural areas where hospitals are not equipped to keep the vaccines at the right temperatures, or do not have the staff to prepare them for injection, will not receive the Pfizer shots. That is more of an obstacle in the United States and Canada, huge countries with vast, sparsely populated regions, than in Britain, which is much more compact.
In Canada, where the military is playing a central role in vaccine distribution, the government is sending shipments to all 10 provinces. The three northern territories will have to wait.
In the United States, FedEx and UPS will ship vaccines from distribution centers to every part of the country. But the holiday season is the busiest time of the year for delivery services, which could slow things down.
How fast will most people get vaccines?
That is even murkier.
Britain, Canada, the United States and the European Union have all followed similar strategies, pre-ordering huge numbers of doses — more than enough to inoculate everyone — from multiple makers, hedging their bets in case some of the vaccines are not approved or some manufacturers have production breakdowns.
Relative to their populations, the United States has ordered far fewer doses than Canada or Britain, and last summer it passed up an offer to increase its advance order from Pfizer. Administration officials say the numbers are misleading, because the government has signed options to buy far more of the vaccine if it sees the need.
But in the face of intense global demand, it is not clear how fast pharmaceutical companies will be able to fulfill the orders they have, much less any additional orders.
And again, the speed of development, approval and production will affect how quickly supplies reach people. A country that places a bigger bet on one vaccine could be much better off than one that relies more heavily on another.
Megan Twohey and Ian Austen contributed reporting.