Both are bivalent vaccines that combine the companies’ original vaccine with one targeting the Omicron sublines BA.4 and BA.5.
Pfizer’s updated vaccine is a 30-mcg dose approved for people 12 and older. Moderna’s updated vaccine is a 50-mcg dose approved for use in people 18 and older.
The shots can be administered after being recommended by the US Centers for Disease Control and Prevention. The CDC’s Vaccine Advisory Group is scheduled to vote Thursday on whether to support the boosters’ recommendation for use. Then the CDC director must approve the recommendation.
An OK from the CDC would mean updated boosters could be given within days — both to older people who may have received a booster just a few months ago, and to younger people who are not eligible for an additional booster during the last wave of cases had .
booster circuit
The updated vaccines do not replace vaccinations for the primary series, but they do replace the booster shot given to people over 12 years of age.
“With today’s approval, the mRNA COVID-19 monovalent vaccines are not approved as a booster dose for persons 12 years and older,” the FDA said.
People 12 years and older are eligible for Pfizer’s bivalent booster vaccine if they have had their primary vaccination course and it has been at least two months since their last vaccine dose. Those 18 and older are eligible for Moderna Boosters on the same schedule.
Individuals who are too young to receive an updated booster shot can still be boosted with the earlier vaccine.
The FDA said it will “work quickly” to evaluate future regulatory submissions for bivalent boosters in younger people. Pfizer said in a press release that it expects to submit an application in early October for approval of its updated booster for children ages 5 to 11, and it is working to prepare an application for children ages 6 months to 4 years.
“We want to ensure that adults and adolescents covered by this approval can receive the most up-to-date version of a booster vaccine, and as such we no longer authorize the monovalent – the original – booster dose to be administered to these populations,” said Dr. Peter Marks , director of the FDA’s Center for Biologics Evaluation and Research, during a news conference.
About two-thirds of the entire US population has been vaccinated against Covid-19 with a first series, according to data from the CDC. But less than half of those with their first streak — and less than a third of the general population — have also gotten a refresher.
There’s no plan yet to phase out the previous vaccines used in the primary series, Marks said, but this is a “transition year” in which people need to make sure they have a “good base that we can build on.” build up…which will help protect us from the unknown.”
“If you haven’t had a booster dose yet, or it’s been several months since your last booster dose, you should start thinking about getting one now,” Marks said.
Officials defend quick approval
On Wednesday, FDA officials defended their fast-track emergency approval of the updated Covid vaccine booster. Pfizer and Moderna filed for approval last week.
“The public can rest assured that the FDA has taken great care to ensure that these updated boosters meet our stringent safety, efficacy and manufacturing quality standards for emergency use approval,” said Marks.
The agency approved these boosters after studies in mice, but before the results of human clinical trials.
This is similar to how annual flu vaccines are tested every year, but it’s a first for Covid-19 vaccines. The approach has sparked some controversy among vaccine experts. In approving, the agency did not call a new meeting of its independent vaccine advisors, who often consider vaccine changes; The advisory group had offered its insights on updating the original vaccine in meetings over the summer.
“Since earlier this year, we have been planning and accumulating our approach for updated boosters,” said FDA Commissioner Dr. Robert Califf during the press conference. “The FDA has extensive experience evaluating strain changes for influenza vaccines and is confident that the data supports these latest booster vaccine approvals.”
In addition to the animal data, the FDA said it based its decision on more than a year of experience with hundreds of millions of doses of mRNA vaccines administered around the world. They also rely on human clinical trials of various bivalent vaccines targeting the original Omicron strain. This vaccine has been approved in the UK but will not be available in the US. More than 1,400 participants have been enrolled in clinical trials of Pfizer’s and Moderna’s bivalent BA.1 vaccines.
Human trials of the bivalent boosters, which combine the companies’ original vaccine with one targeting the Omicron BA.4 and BA.5 sublines, have begun, Marks said Wednesday. Data from these studies are expected in a month or two.
Milestone in vaccine
“America is the first country in the world to have a bivalent vaccine approved, where the bivalent vaccine targets the viruses out there,” said Dr. Ashish Jha, who is leading the White House’s Covid-19 response, in a phone interview with CNN on Wednesday.
“We try to do this every year because of the flu. We almost never hit the mark. This has cost the FDA a lot of work. It was about getting into the science, getting into very good modeling from the companies, that they’re making vaccines that are going to be coordinated.”
The Omicron BA.5 subvariant has dominated transmission in the United States for more than two months. Last week it caused 89% – nearly 9 out of 10 – new Covid infections in this country, according to the CDC’s latest estimates.
A new offshoot of the BA.4 variant, BA.4.6, has slowly gained traction and claims second place. Across the country, it caused about 8% of new infections last week, but it’s picked up more in the Midwest — Kansas, Iowa, Missouri and Nebraska — causing an estimated 17% of new infections there.
CNN’s Deidre McPhillips contributed to this report.