LONDON — Britain gave emergency authorization on Wednesday to Pfizer’s coronavirus vaccine, leaping ahead of the United States to become the first Western country to allow mass inoculations against a disease that has killed more than 1.4 million people worldwide.
The decision kicked off a vaccination campaign with little precedent in modern medicine, encompassing not only ultracold dry ice and trays of glass vials but also a crusade against anti-vaccine misinformation.
Britain beating the United States to authorization — on a vaccine co-developed by the American pharmaceutical giant Pfizer, no less — may intensify pressure on U.S. regulators, who are already under fire from the White House for not moving faster to get doses to people. And it has stirred up a global debate about how to weigh the desperate need for a vaccine with the imperative of assuring people that it is safe.
“Help is on its way with this vaccine — and we can now say that with certainty, rather than with all the caveats,” the British health secretary, Matt Hancock, said on Wednesday, as the government exulted in the authorization.
While the go-ahead bodes well for Britain, which broke from the European Union’s regulatory orbit to approve the shot early, it will have no effect on the distribution of the hundreds of millions of doses that other wealthy countries have procured in prepaid contracts.
It also offers little relief to poorer countries that could not afford to buy supplies in advance and may struggle to pay for both the vaccines and the exceptional demands of distributing them.
The Pfizer vaccine, developed with BioNTech, a smaller German firm, must be transported at South Pole-like temperatures, a requirement that could dictate who will be vaccinated first in Britain: Nursing-home residents were supposed to be the top priority under an advisory committee’s plans, but efforts to limit transportation of the vaccine and ensure it remains cold may mean that National Health Service staff will receive the shots first.
The government said on Wednesday that 800,000 doses would be available by next week for health workers to begin administering. For Britain, which has suffered one of Europe’s highest per capita death tolls from the virus, the decision by its drug regulator testified to a vaccination strategy that has been the most aggressive in the West.
After the government strengthened an old law that allows Britain to step out from under the European Union’s regulatory umbrella in public health emergencies, its Medicines and Healthcare Products Regulatory Agency fast-tracked a review of the Pfizer vaccine, which was 95 percent effective in a late-stage trial.
The White House, concerned that Britain would approve a vaccine first, summoned Dr. Stephen Hahn, the commissioner of the Food and Drug Administration, for a meeting on Tuesday. A panel of outside advisers to the F.D.A. is scheduled to meet on Dec. 10 to decide whether the agency should grant emergency authorization to the Pfizer vaccine.
While American regulators pore over raw data from vaccine makers to validate their results, their counterparts in Britain and elsewhere in Europe lean more heavily on companies’ own analyses. The European Union is set to conduct its own review of the Pfizer and BioNTech vaccine, after the companies submitted their final application to the bloc’s health authorities on Tuesday.
The global race to develop a vaccine is poised to shatter records for time to market. Around the world, researchers are testing 57 vaccines in clinical trials, and nearly 100 others are being tested in animals or cells. China and Russia have approved vaccines without waiting for the results of late-stage trials, known as Phase 3, which experts say raises serious risks.