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In milestone, FDA clears coronavirus vaccine from Pfizer, BioNTech for emergency use

The Food and Drug Administration on Friday granted emergency authorization to Pfizer and BioNTech's coronavirus vaccine, clearing its use after a historic 10-month research sprint and a rapid review that culminated Thursday with the endorsement of an independent advisory committee.

With the vaccine's authorization, millions of vulnerable U.S. residents could soon have a shot at protection from a resurgent COVID-19 pandemic that has claimed hundreds of thousands of lives and sickened millions. Daily case counts and deaths have hit new highs in the weeks following Thanksgiving and more than 100,000 people are currently hospitalized.

Initial supplies, however, are extremely limited, forcing public health officials to prioritize which groups should receive the vaccine first. Healthcare workers and nursing home residents, who have fallen ill and died from COVID-19 in disproportionate numbers, are expected to begin receiving the vaccine within days, as Pfizer began manufacturing while clinical trials were still underway.

Some 2.9 million doses are expected to be available initially, with the U.S. holding some in reserve to ensure people receive the second of two doses that vaccination requires.

"While not an FDA approval, today's emergency use authorization of the Pfizer-BioNTech COVID-19 vaccine holds the promise to alter the course of this pandemic in the United States," said Peter Marks, director of the FDA division that reviews vaccines, in a statement.

Authorization of a vaccine within a year of scientists identifying the new coronavirus is a scientific milestone that, at the pandemic's outset, looked unattainable.

"In my wildest dreams, I thought it would be fast. But fast means, if it [typically] takes seven years, maybe you can get it down to a couple of years," said Anthony Fauci, in a Dec. 11 interview with the editor of JAMA. "Now it's our challenge to convince people that this wasn't rushed in a reckless way."

Yet the FDA has been under immense pressure to speed an approval and, on Friday, the Trump administration reportedly told agency head Stephen Hahn to submit his resignation if Pfizer and BioNTech's vaccine was not cleared by the end of the day. The vaccine was cleared by regulators in the U.K., Bahrain, Canada, Saudi Arabia and Mexico earlier this month.

The emergency use authorization, a special type of approval used in public health crises, came one day after a panel of FDA advisers voted 17-4 to recommend use of the shot.

Two of the four "no" votes came from committee members who wanted to recommend the vaccine only for people aged 18 or older, rather than include 16- and 17-year olds as the FDA had advocated. The FDA's final decision authorized its use for people as young as 16.

The regulator, along with its advisers, was persuaded by a massive trial that enrolled 44,000 people and randomly assigned them to receive either Pfizer and BioNTech's vaccine or a placebo.

Trial results announced Nov. 18 showed the vaccine to be 95% effective in preventing COVID-19, easily surpassing the 50% threshold set by the FDA earlier this year. Vaccination was similarly protective in older adults and in individuals of different races or ethnicities, according to detailed data presented at Thursday's meeting.

"The data are pretty clear cut so it's a very straightforward decision," said Philip Grant, an infectious disease doctor at Stanford University Medical Center.

Importantly, Pfizer and BioNTech also proved their vaccine is safe, with no unexpected or serious adverse reactions observed in the study. Many participants did experience injection site pain, fever, headache and fatigue, generally mild or moderate in nature.

While the companies first reported positive results from their Phase 3 study on Nov. 9, they waited 11 more days before submitting an application in order to collect at least two months' of safety follow-up on half of trial participants. Most side effects to vaccines emerge within 40 to 60 days, which motivated the FDA to set the two-month requirement.

Four cases of Bell's palsy — temporary weakness or paralysis in one side of the face — were reported among trial volunteers who received the vaccine, three of which had resolved. FDA reviewers, however, noted the frequency was no greater than what would be expected in the general population.

Regulators in the U.S. and elsewhere are also on now watch for signs of allergic reactions to vaccination among individuals with a history of severe allergies, after two people in the U.K. had reactions after receiving their first shot. The authorization from the FDA instructs medical personnel not to give the vaccine to people who have a history of severe allergic reaction to any of its ingredients.

The emergency clearance for Pfizer and BioNTech's shot is expected to be followed quickly by one for a similar type of vaccine developed by Moderna. An advisory committee is scheduled to meet and vote on the company's application on Dec. 17.

Study results showed Moderna's vaccine, which was developed in collaboration with U.S. government scientists, to be similarly effective against COVID-19.

The shots' high efficacy could help convince skeptical portions of the public who have indicated in polls they'd be cautious or unlikely to get a vaccine.

"There will be less vaccine hesitancy in March than there will be in January, and then a lot less in May than in March," said Larry Corey, a virologist at the Fred Hutchinson Cancer Research Center and co-leader of a vaccine trial network.

It's still unclear, however, whether either vaccine can protect against infection and transmission, as well as disease. Data from Pfizer could come soon, however, Kathrin Jansen, the company's head of vaccine research and development, told the FDA's advisers Thursday.

Both companies have worked feverishly to scale up manufacturing in preparation for an approval, but both will only have limited supplies to offer the U.S. and other countries in which their vaccines are approved.

Pfizer and BioNTech, which make their vaccine at sites in Michigan and in Puurs, Belgium, expect to make 50 million doses by the end of 2020, only some of which is reserved for use in the U.S. Production should ramp up considerably in 2021, when the two companies expect to manufacture up to 1.3 billion doses.

Moderna has said it can produce 20 million doses for the U.S. this month, and another 85 million to 100 million by the end of March.

The U.S. initially preordered 100 million doses of each vaccine, an amount that would cover less than a third of the U.S. population. According to The New York Times, the U.S. passed up its chance to order more doses from Pfizer under an option it had negotiated, although officials dispute the Times' account.

On Friday, Moderna announced the U.S. had agreed to purchase another 100 million doses for delivery in the second quarter of 2021. The U.S. also appears to be counting on approvals for several vaccines still in testing by AstraZeneca, Johnson & Johnson and Novavax. Deals with the three companies reserve some 500 million doses for the U.S.

Moncef Slaoui, the scientific leader of the U.S.'s "Operation Warp Speed" vaccine program, recently predicted 100 million U.S. residents will get a vaccine by the end of February — an ambitious target even if two shots are approved.

Further complicating roll-out plans are the temperature requirements for Pfizer and BioNTech's vaccine, which must be shipped and stored at minus 70 degrees Celsius. Pfizer built shipping containers that will use dry ice to keep doses cold, and is handling distribution on its own.

Dry ice has been in short supply this year, requiring logistics companies to beef up production to meet the demand of transporting vaccines.

Moderna's vaccine must also be kept cold, but at a more moderate minus 20 degrees Celsius.