An example of a vial that will carry the COVID-19 vaccine produced by Pfizer and BioNTech sits on display during a Senate subcommittee hearing Thursday.
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An example of a vial that will carry the COVID-19 vaccine produced by Pfizer and BioNTech sits on display during a Senate subcommittee hearing Thursday. / Pool/Getty Images

Federal officials have authorized emergency use of the COVID-19 vaccine produced by Pfizer and BioNTech in a landmark decision that promises to alter the fight against the coronavirus radically in the United States.

The Food and Drug Administration released its letter to Pfizer granting the authorization Friday evening.

"It is nothing short of a medical miracle to have FDA authorization of a vaccine for COVID-19 just over 11 months since the virus was made known to the world," said Health and Human Services Secretary Alex Azar in a statement. "Vaccines will help bring this pandemic to an end, which is all the more reason to double down on the public health measures we need to stay safe in the coming months."

The FDA's decision, which comes just one day after an advisory panel overwhelmingly offered its endorsement, makes the vaccine the first to obtain a green light for widespread distribution in the United States.

Several other countries have previously granted such an authorization to the Pfizer vaccine — including the U.K., where a sweeping immunization program kicked off earlier this week.

HHS' Azar, speaking with ABC's Good Morning America, said earlier Friday he expects that "we could be seeing people [in the U.S.] getting vaccinated Monday or Tuesday of next week."

In the first push after authorization, the government expects 2.9 million doses of vaccine to go out. Shipments are expected to begin within 24 hours. Government officials have said they'll be able to supply enough doses of vaccine for 20 million people by the end of the year.

"We have clear evidence that the vaccine is highly effective at least three months after getting the first dose, and given the other data they presented, I think it's likely to be effective for much longer," Dr. Paul Offit told NPR's Morning Edition on Friday in advance of the FDA announcement.

Offit is the director of the Vaccine Education Center at Children's Hospital of Philadelphia and one of the 17 members of the advisory board to vote to recommend the vaccine Thursday. Four of the advisers voted against it, while one abstained.

Documents released by the FDA, including a vaccine fact sheet and prescribing instructions, addressed several issues that came up during the advisory panel meeting Thursday.

Despite some disagreement by experts on the advisory panel over the adequacy of evidence to support use of the vaccine in people as young as 16, the vaccine was authorized for use in people 16 and older.

The vaccine shouldn't be given to people with a history of severe allergic reactions to any of the ingredients in the vaccine, the instructions say. Medical treatment for serious allergic reactions that occur immediately after injection must be available. And, in an apparent nod to the report of two cases after vaccination in the U.K., the fact sheet acknowledges that severe allergic reactions have occurred following immunization with the vaccine outside clinical trials.

The prescribing instructions don't preclude use of the vaccine in pregnant women or women who are breastfeeding, but they say that there isn't enough information to assess the effects of the vaccine or its risks under those circumstances.

"We know that the vaccine has been given to tens of thousands of people safely. So we can say, at least with comfort, that it doesn't cause an uncommon, serious side effect," Offit said, adding the caveat that this doesn't necessarily rule out the possibility that a rare side effect may crop up later.

"But I think we know enough. You know, when you agree to move forward with a product, it's not whether you know everything. It's whether you know enough to say that the benefits outweigh what at this point are theoretical risks," Offit added.

That's a key consideration with the authorization process, which has unfolded against the backdrop of a pandemic currently killing record numbers of people per day in the United States. Nearly 300,000 people in the U.S. have died of COVID-19 since the start of the year, according to data compiled by Johns Hopkins University — a staggering death toll that now exceeds the number of Americans killed in battle during all of World War II.

That means an urgent quandary for health regulators around the world, many of whom, including in the U.S., have departed from the usual approval process to ensure a speedier response to the pandemic. The FDA has relaxed its usual review mechanism to allow drugs, tests and vaccines to get out more quickly than the usual, more stringent requirements for full-blown approval would otherwise allow. This speedier path is called emergency use authorization.

The Pfizer vaccine, which is administered in a pair of doses three weeks apart, has been demonstrated to be 95% effective in clinical trials.

But it's not the only vaccine to show promising results.

Another vaccine, this one produced by Moderna, has been more than 94% effective in trials and is currently awaiting its own authorization by the FDA. At a public meeting on Dec. 17, a panel of expert advisers to the agency will meet to consider the evidence for the vaccine and make a recommendation about it.

Scott Hensley contributed to this report.

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