U.S. regulators approved Pfizer-BioNTech’s COVID-19 vaccine for emergency use Friday, a major step for a shot developed in record time and a milestone in combating a pandemic that has killed nearly 300,000 Americans this year.

What You Need To Know

  • The FDA has approved Pfizer’s COVID-19 vaccine for emergency use Friday, the first in the U.S.

  • The company could start shipping out its first doses within 24 hours, per Operation Warp Speed’s timeline, meaning the first Americans could be vaccinated for COVID-19 early next week

  • The authorization comes one day after an FDA advisory panel endorsed the vaccine, recommending its use in Americans 16 and older

  • Top health officials say they expect to have 20 million Americans get their first doses by the end of the year

The company could start shipping out its first doses within 24 hours, per Operation Warp Speed’s timeline, meaning the first Americans could be vaccinated for COVID-19 early next week. 2.9 million doses will go out in the first wave, divided between U.S. states, territories and major cities based on population.

The authorization comes one day after an FDA advisory panel endorsed the vaccine, recommending its use in Americans 16 and older. 

“The FDA’s authorization for emergency use of the first COVID-19 vaccine is a significant milestone in battling this devastating pandemic that has affected so many families in the United States and around the world,” said FDA Commissioner Stephen M. Hahn, M.D.

“Today’s action follows an open and transparent review process that included input from independent scientific and public health experts and a thorough evaluation by the agency’s career scientists to ensure this vaccine met FDA’s rigorous, scientific standards for safety, effectiveness, and manufacturing quality needed to support emergency use authorization," he added. "The tireless work to develop a new vaccine to prevent this novel, serious, and life-threatening disease in an expedited timeframe after its emergence is a true testament to scientific innovation and public-private collaboration worldwide.”

In a press conference Saturday, Hahn reiterated that regulators did not sacrifice safety for speed.

"Efficiency does not mean any cutting of corners," he said. "Medical products are still undergoing rigorous study and clinical trials. Important safety checks remain in place. The FDA’s review teams continue, as they have always done, to comb through the data submitted by companies regarding their medical products."

In a video posted to social media, President Donald Trump announced the approval, calling the effort to produce a vaccine a "medical miracle" and "one of the greatest scientific accomplishments in history."

In the FDA’s initial review of Pfizer’s data, the agency confirmed the shot is 95 percent efficacious and safe for most adults. The vaccine was developed in less than eleven months, an expedited timeline made possible by significant financial investment up front and by global efforts to quash a pandemic that touched nearly every corner of the globe. 

While Pfizer has very limited data from trials on teenagers, young children and pregnant women have not been studied at all in the company’s phase three trials.

In a still unfinished study of nearly 44,000 people, the FDA found the vaccine was safe and more than 90% effective across recipients of different ages, including older adults, races and those with health problems that put them at high risk from the coronavirus. It’s authorized for people age 16 and up.

Emergency use means the vaccine still is experimental. Most important for would-be recipients to know:

  • Some protection begins after the first dose, but it takes a second dose three weeks later for full protection. It’s unclear how long protection lasts.
  • The vaccine protects against COVID-19 illness, but no one yet knows if it can stop the silent, symptomless spread that accounts for roughly half of all cases. The ongoing study will attempt to answer that but for now, the vaccinated still will need to wear a mask and keep their distance.
  • Expect a sore arm and some flu-like symptoms such as fever, fatigue, headache and chills after the second dose. While uncomfortable, those reactions only last about a day. “That’s just your immune system working. It’s a good thing,” Offit said.
  • Authorities are investigating several allergic reactions reported in Britain by health workers with a history of severe allergies. The FDA said people must have treatments for allergic reactions on hand before they are administered the COVID-19 vaccine, and not give it to those with a known history of severe allergic reactions to any of its ingredients.
  • Every vaccine recipient must be given an FDA-written fact sheet about the vaccine and its known risks and benefits.
  • FDA didn’t forbid the vaccine’s use in pregnant women but noted there isn’t enough evidence to determine its safety in that group.

States and localities have already submitted detailed plans for vaccine distribution, and the first doses are expected to go to health care workers and residents of long-term care facilities. Some health care providers have already started scheduling their staff for vaccinations early next week. 

But the number of people vaccinated in the first wave will be limited. While Pfizer has more than six million doses in stock, about half are being held back as the second doses for the Americans who get vaccinated first. Both Pfizer and Moderna’s vaccines require two shots.

From there, the company is expected to roll out more doses each week at a “continuous cadence,” according to General Gustave Perna, who oversees distribution for Operation Warp Speed. 

Top health officials say they expect to have 20 million Americans get their first doses by the end of the year. That number would ideally increase to 30 million in January and 50 million in February, meaning the country’s most vulnerable populations could have access to a vaccine by March 1. 

Those numbers depend on the authorization of a similar vaccine from Moderna and the National Institutes of Health, which is one week behind Pfizer in the approval process. On Friday, the administration announced the purchase of another 100 million doses of Moderna’s vaccine, bringing the total to 200 million.

Health officials are also looking to a vaccine from Johnson & Johnson, which may be ready to submit for an EUA by the end of January, according to Dr. Moncef Slaoui, who oversees vaccine development. 

“We may be able to accumulate another 30 to 40 million if this vaccine gets approved,” Dr. Slaoui said.

Still, as many as 200,000 more Americans could die by the time the vaccine is widely available, according to projections from a key model at the University of Washington. Officials expect to have enough doses for the entire U.S. population by mid-2021, if the timeline remains on track.

Until then, experts have recommended people continue to adhere to public health guidelines, such as distancing and wearing masks, especially since it’s unclear whether someone who gets vaccinated can still transmit the virus or not.

On Thursday, representatives for Pfizer and the FDA also faced questions from agency advisers about potential blindspots in the vaccine’s data.

A new question is whether the vaccine is potentially dangerous to people with a history of severe allergies.

On Wednesday, British officials flagged the issue after two people had anaphylactic reactions after getting the shot. Both carried an EpiPen for their allergies.

In Thursday’s meeting, panel members called for more studies to determine whether people with a history of allergies are safe to get the shot. 

“You’re talking about tens of millions of people who are not going to get this vaccine because of comments that were made,” said Dr. Paul Offit, Director of the Vaccine Education Center at the Children's Hospital of Philadelphia. 

U.K. regulators approved Pfizer’s vaccine last week and began vaccinating people on Tuesday, becoming the first Western nation to do so. Canada approved the vaccine Wednesday.

An emergency authorization does not equate to a full FDA approval, and Pfizer will have to carry out more trials to receive an official license for the vaccine. The trials are likely to include studies of younger children, pregnant women and a closer look at allergic reactions.

Pfizer designed custom shipping boxes for the vaccine, which must be stored at about -70°C. They can carry anywhere from 975 doses — the minimum order amount — to 5,000 and will be handled by UPS and FedEx. 

The box will have a layer of dry ice on the bottom, a thermal container to hold the vaccines on top of that, then another layer of dry ice, according to a presentation from Wes Wheeler, President of UPS Healthcare, at the White House this week.

"The preparation for this has been intense," Jim Mayer, a spokesman for UPS, said Thursday. "We have been at this for months – planning; putting the right people, the right technology in place. At this point, UPS is 100% ready to go.”

Before the box is sealed, another, more-technical layer goes on top, which contains both a temperature monitor and a GPS tracking device. The Pfizer vaccine can stay cold enough in its shipping box for ten days, if unopened.

Already, vaccine kits are being shipped out across the country. They include face masks, alcohol wipes, needles and syringes – essentially everything needed for vaccination except the dose itself. 

The Associated Press contributed to this report.