The U.S. Food and Drug Administration on Wednesday gave the green light to updated COVID booster shots from both Pfizer and Moderna that target Omicron variants, paving the way for the shots to get into American arms within a few days.
“The FDA has been planning for the possibility that the composition of the COVID-19 vaccines would need to be modified to address circulating variants," Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in an agency news release announcing the emergency approval.
"We sought input from our outside experts on the inclusion of an Omicron component in COVID-19 boosters to provide better protection against COVID-19. We have worked closely with the vaccine manufacturers to ensure the development of these updated boosters was done safely and efficiently. The FDA has extensive experience with strain changes for annual influenza vaccines. We are confident in the evidence supporting these authorizations," Marks added.
FDA Commissioner Dr. Robert Califf urged Americans to get the new boosters.
“As we head into fall and begin to spend more time indoors, we strongly encourage anyone who is eligible to consider receiving a booster dose with a bivalent [targets both the original virus and the Omicron variants] COVID-19 vaccine to provide better protection against currently circulating variants,” he said in the news release.
Now that the FDA has given its blessing, a vaccine advisory panel for the U.S. Centers for Disease Control and Prevention is set to meet Thursday and Friday to weigh who should get the updated boosters. Once the panel makes its recommendation, CDC Director Dr. Rochelle Walensky is expected to sign off on those recommendations. The approvals will come before the possible emergence of a winter surge in COVID-19 cases.
Moderna's updated booster was authorized for those 18 and older, while the Pfizer booster was approved for those 12 and older, the FDA said. It should be given at least two months after primary vaccination or the original boosters.
Although these newest boosters have only been tested in mice so far, Marks told The New York Times last week that the agency has “extremely good” data showing that the shots are safe and will be effective. “How confident am I?” he said. “I'm extremely confident.”
Dr. Anthony Fauci, President Biden's chief medical adviser, also told the Times that using animal data was “not anything different than we always do” in updating the flu vaccine each year.
Marks added that other evidence included the extensive track record with the existing vaccines and a series of earlier human trials with variant-specific formulations.
“I take great issue with those who say, ‘Oh, you're just approving this with mouse data,'” he said. “We're authorizing this with the totality of the evidence that we have.”
Moderna has begun human trials of its new booster, while Pfizer plans to do the same.
The main target of the new shots? The BA.5 variant, which now accounts for nearly 90% of all new U.S. cases.
“We have really got to do better to protect the American public,” Fauci said. “We are in the middle of a BA.5 outbreak here, and we are nowhere near where we want to be.”
Despite that, U.S. health officials haven't managed to convince most Americans that they need more shots at this point in the pandemic. Only about two-thirds of the population has had the primary series of two shots, and far fewer have received booster doses.
And not all scientists are on board with the new boosters: Some maintain that the original vaccines provide strong protection against severe disease.
“Deaths are concentrated in unvaccinated people and people with serious health conditions,” John Moore, a virologist at Weill Cornell Medicine in New York City, told the Times. He added that the extra protection the new shots would provide against infection alone would likely be weak.
“My issue all along has been: Is there enough data to really justify the effort?” Moore said. “The potential downside is, if the public thinks that this Omicron-containing booster is some kind of magic bullet that will give them super-strong protection from infection, is there a risk that they will change their behavior to increase their exposure?”
Jeremy Kamil, a virologist at Louisiana State University Health Shreveport, told the Times that while he supports the new boosters, many people already have immunity because of recent infections.
“Even if we get this out in the next 10 days, how many people are left who haven't gotten Omicron?” he said.
As of mid-August, the federal government had bought more than 170 million doses of the updated version of the vaccines, the Times reported. This month, the CDC laid out detailed plans to offer the shots, warning that the supply would be “sufficient, but finite.”
Visit the U.S. Centers for Disease Control and Prevention for more on COVID vaccines.