A coronavirus vaccination center is prepared at the fair grounds in Hamburg. (Axel Heimken/AFP/Getty Images)

ROME — The European Union's drug regulator on Monday authorized the use of the first coronavirus vaccine for the bloc, enabling member countries to begin inoculations next week in an urgent but complicated fight to ease the pandemic.

The authorization of the Pfizer-BioNTech vaccine could stand as a symbolic turning point in a pandemic that has killed more than 300,000 Europeans, caused the deepest recession since the E.U.’s formation and sent many countries back into lockdown for the holidays. Countries are also halting flights to and from Britain, alarmed about an emerging variant of the virus detected in England that is said to be more transmittable.

E.U. policymakers have portrayed the vaccine rollout as a chance to show the bloc’s unity in the face of the virus threat. Doses will be allocated to all 27 E.U. nations based on population, not wealth, and each country will pay the same price. European Commission President Ursula von der Leyen expressed hope that countries would start the vaccination in unison in the days after Christmas.

In the end, though, the launch may be a bit disunited, with vaccines being administered in a rolling wave in the coming weeks.

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Some countries have struggled to get in place the ultracold freezers necessary to store the Pfizer-BioNTech vaccine. Others are still tweaking plans about how they will decide who gets the first inoculations — generally, front-line health workers, as well as residents and staffers of nursing homes, but each country has its own list. And the first shipments may be modest: Media in Estonia reported last week that one company — which was not identified — wanted to send 10,000 doses in the first wave, enough for just 5,000 people in the country of 1.3 million.

“We are not yet at a turning point,” Emer Cooke, executive director of the European Medicines Agency, said in announcing the Pfizer-BioNTech authorization. “It will take time to roll out vaccines in sufficiently large numbers to enable all of our citizens to be protected.”

Some health officials are grumbling that Europe has already fallen behind, with the United States, Britain and Canada having authorized the Pfizer-BioNTech vaccine earlier this month. The United States has also authorized a vaccine developed by Moderna, which Europe’s regulator will review for authorization on Jan 6.

At an E.U. summit this month, some leaders pushed the European Medicines Agency to speed up the decision-making, and the regulator bumped up its meeting from Dec. 29 to Dec. 21, saying it had received new information from the vaccine producers. E.U. policymakers who have defended the pace say that the best way to ensure widespread public confidence in the safety of the vaccines is not to appear to cut any corners on studies of safety and efficacy.

The European Medicines Agency is using a more fleshed-out process for vaccine approval compared with the United States, which authorized the Pfizer-BioNTech vaccine on an emergency basis. The European Commission, the E.U.’s executive branch, will need to sign off on the deal, which von der Leyen said could come later Monday.

“Now we will act fast,” she said on Twitter.

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Pfizer, partnering with BioNTech, and Moderna have created promising vaccines that scientists hope will lead to more medical breakthroughs using mRNA. (Video: Joshua Carroll, Brian Monroe/The Washington Post)

The pressures are immense. More than 3,000 people in Europe are dying of the virus every day.

Many E.U. countries, including Italy, Spain and Germany, say they will begin the first shots on Dec. 27. Germany has already built mass-vaccination centers on soccer grounds and old bus depots.

“The primary goal of our vaccination drive is to protect the weakest,” those in nursing homes who are 80 or older, German Health Minister Jens Spahn said.

Denmark, though, said the first shots will not be feasible until early January.

Scientifically, the progress in halting the pathogen has been unprecedented; never before have drugmakers moved so quickly from development to trials, building vaccines that — in the case of Pfizer-BioNTech and Moderna — have proved roughly 95 percent effective against the virus in clinical trials. But distribution is proving trickier than development. The United States has already fallen behind schedule, with state governors complaining that they have been receiving fewer doses than initially promised.

The vaccine purchasing in Europe has been a centralized affair, handled largely by the European Commission, which has locked in contracts for 1.3 billion doses of six vaccines in various stages of development.

The E.U. will receive 200 million doses of the Pfizer-BioNTech vaccine, with an option to buy 100 million more. It bought an additional 80 million doses of the Moderna vaccine, with an option to request another 80 million — but officials have said they don’t expect deliveries from Moderna until later next year.

Some of the other vaccines the E.U. has bet heavily on are further behind in development. After a setback, a vaccine being developed by the French company Sanofi probably will not be ready until late 2021. The E.U. also has a deal with AstraZeneca for 400 million doses of a vaccine developed with the University of Oxford, and though initial data suggests its efficacy is lower — 70 percent overall — it costs less than Pfizer’s and does not need to be frozen.

The German newsmagazine Der Spiegel said Europe erred by buying too little and betting on the wrong producers, while turning down a far larger first-round order from Pfizer-BioNTech.

At least two E.U. countries, Germany and Hungary, have sought to purchase more vaccines on the side, a step that may also ultimately undermine European unity, because the limited supply means that any doses that go exclusively to one country lead to fewer being available for the E.U. as a whole in the short term.

Germany is lining up extra doses of the Pfizer-BioNTech vaccine, a step Spahn justified by noting that the country had supplied crucial research funding at an early stage of the vaccine’s development. Hungary has bought the Russian Sputnik V vaccine for use within its borders.

Birnbaum reported from Riga, Latvia. Quentin Ariès in Brussels contributed to this report.

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