What does full FDA approval of a vaccine do if it's already authorized for emergency use?
BY JENNIFER GIROTTO
UNIVERSITY OF CONNECTICUT
THE CONVERSATION
(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.)
Thirty percent of unvaccinated American adults say they're waiting for the COVID-19 vaccines currently authorized for emergency use to be officially approved by the U.S. Food and Drug Administration. The FDA has since granted that approval for those age 16 and older for the Pfizer-BioNTech vaccine on Aug. 23, 2021. What had to happen for the FDA to advance from emergency use authorization, or EUA, to full approval?
I'm a pharmacist who trains other pharmacists, health care providers and students on why, when and how to administer vaccines. Emergency use authorization, while streamlining the regulatory process so the vaccine is more quickly available to the public, still follows a rigorous process the FDA requires to ensure vaccine safety and effectiveness. The difference is that more time has passed and more data is available for review when a company applies for full approval.
EUA and full approval share similar first steps
For both emergency authorization and full approval, for COVID-19 vaccines, the FDA first requires initial safety studies on a small number of people. Here, researchers document potential adverse events, or side effects, that the vaccine may cause. Researchers also determine the safest and most effective dose of the vaccine.
Once the vaccine is determined to be safe and an optimal dose identified, researchers will create larger studies to ascertain how well it works in a controlled setting where some people are given the vaccine while others are given a placebo.
It is important to note that the number of people who participated in the initial COVID-19 safety studies was similar to that in the safety studies of other commonly used vaccines, including vaccines for tetanus, diphtheria, whooping cough and meningitis. Over 43,000 adults participated in the early phases of the Pfizer-BioNTech clinical trial, over 30,400 in Moderna's and over 44,000 in Johnson and Johnson's. Half the participants in each study were given a vaccine, while the other half were given a placebo.
Where EUA and full approval differ
From this point on, emergency use authorization and full FDA approval for COVID-19 vaccines follow different clinical study requirements.
For the emergency use authorization, the FDA requires at least half of the participants of the original studies to be followed for at least two months post-vaccination. This is because the vast majority of vaccine-related side effects occur right after vaccination.
Full FDA approval, on the other hand, requires participants in the original studies to be followed for at least six months. Reviewers look at data from the same study participants but collected over a longer period of time. All adverse events are examined. The manufacturer must also provide more detailed manufacturing plans and processes, as well as a higher level of oversight and inspections. All of this adds significantly more time to the review process.
Both Pfizer and Moderna began their rolling submission for approval in the FDA's "Fast Track" process, designed to speed up review. This allows the companies to submit portions of their approval application to the FDA for review as they're completed.
Full FDA approval will initially apply to only the same age groups that were tested in the original emergency use authorization. This means that the vaccine has been approved first for people ages 16 and up for Pfizer, and will likely be approved for those 18 and up for Moderna. Rolling submission will allow approval of the vaccine for younger groups as more data becomes available.
Different timelines, same rigorous requirements
Full FDA approval is a milestone that may help build confidence among the vaccine hesitant about the safety of the vaccines. But the true test of the vaccine came when it first gained emergency use authorization. Then, researchers identified the majority of its potential side effects and proved its ability to protect against severe disease.
WASHINGTON (AP) — The U.S. gave full approval to Pfizer's COVID-19 vaccine on Monday, a milestone that may help lift public confidence in the shots as the nation battles the most contagious coronavirus mutant yet.
The vaccine made by Pfizer and its partner BioNTech now carries the strongest endorsement from the Food and Drug Administration, which has never before had so much evidence to judge a shot's safety. More than 200 million Pfizer doses already have been administered in the U.S. — and hundreds of millions more worldwide — since emergency use began in December.
"The public can be very confident that this vaccine meets the high standards for safety, effectiveness and manufacturing quality the FDA requires of an approved product," said acting FDA Commissioner Janet Woodcock. "Today's milestone puts us one step closer to altering the course of this pandemic in the U.S."
The U.S. becomes the first country to fully approve the shot, according to Pfizer, and CEO Albert Bourla said in a statement he hoped the decision "will help increase confidence in our vaccine, as vaccination remains the best tool we have to help protect lives."
U.S. vaccinations bottomed out in July. As delta fills hospital beds, shots are on the rise again — with a million a day given Thursday, Friday and Saturday. Just over half of the U.S. population is fully vaccinated with one of the country's three options, from Pfizer, Moderna or Johnson & Johnson.
The FDA's action also may spur more vaccine mandates by companies, universities and local governments. This month New York City, New Orleans and San Francisco all imposed proof-of-vaccination requirements at restaurants, bars and other indoor venues. At the federal level, President Joe Biden is requiring government workers to sign forms attesting that they've been vaccinated or else submit to regular testing and other requirements.
Anxious Americans increasingly are on board: Close to 6 in 10 favor requiring people to be fully vaccinated to travel on airplanes or attend crowded public events, according to a recent poll by The Associated Press-NORC Center for Public Affairs Research.
"Mandating becomes much easier when you have full approval," said Dr. Carlos del Rio of Emory University. "I think a lot of businesses have been waiting for it."
The FDA, like regulators in Europe and much of the world, initially allowed emergency use of Pfizer's vaccine based on a study that tracked 44,000 people 16 and older for at least two months — the time period when serious side effects typically arise.
That's shorter than the six months of safety data normally required for full approval. So Pfizer kept that study going, and the FDA also examined real-world safety evidence in deciding to fully license the vaccine for people 16 and older, those studied the longest. Pfizer's shot still has emergency authorization for 12- to 15-year-olds.
Even after hundreds of millions of shots, serious side effects — such as chest pain and heart inflammation in teens and young adults — remain exceedingly rare, the FDA said.
As for effectiveness, six-month tracking of Pfizer's original study showed the vaccine remained 97% protective against severe COVID-19. Protection against milder infection waned slightly, from a peak of 96% two months after the second dose to 84% by six months.
Those data came before the extra-contagious delta variant began spreading, but other data from the Centers for Disease Control and Prevention shows the vaccine is still doing a good job preventing severe disease caused by that mutant.
As for all the talk about booster doses, the FDA's licensure doesn't cover those. The agency will decide that separately.
The FDA already is allowing emergency use of a third dose of either the Pfizer or Moderna vaccine for people with severely weakened immune systems, such as organ transplant recipients who don't respond as strongly to the usual two shots. For everyone else who got those vaccinations, the Biden administration is planning ahead for booster starting in the fall — if the FDA and CDC agree.
Also still to be decided is vaccination of children under 12. Both Pfizer and Moderna are studying youngsters, with data expected in the fall.
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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education. The AP is solely responsible for all content.
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