A group of advisers to the Food and Drug Administration on Thursday backed the agency’s plan to simplify COVID-19 vaccine regimens, recommending that both initial and booster doses target the same coronavirus strains.
The committee, made up of infectious disease experts, voted 21-0 that all vaccine doses should have the same composition. Currently, the first two doses of Pfizer’s and Moderna’s vaccines target the original coronavirus strain, while the boosters are “bivalent,” or matched to both the original and omicron variants. Authorized shots from Novavax and Johnson & Johnson, which are little used in the U.S., are aimed at just the original strain.
“Today's vote marks a big practical win for the American people,” said Ofer Levy, a physician at Boston Children’s Hospital and a committee member. “This is going to really simplify things. There's more work ahead .. but this will be a big win.”
The FDA typically follows the committee’s advice, although it isn’t required to do so.
Advisers favored the proposed approach for its potential to make COVID-19 vaccination less confusing by reducing the number of dose types available. Having matching primary and booster doses could also ease the administrative burden on pharmacists and healthcare providers giving shots.
“There's so much confusion about these different formulations that I think anything we can do to ease up on that confusion and simplify things is going to be a good thing,” said Archana Chatterjee, dean of the Chicago Medical School at Rosalind Franklin University and an FDA adviser.
The committee also saw the FDA’s proposal as a way to keep pace with a changing virus. They supported periodic updates to tailor the vaccines against emerging strains or subvariants, such as the BQ.1 and XBB.1.5 that are now predominant in the U.S.
“I think it is important to try and get closer to the strains that are circulating,” said Paul Offit, a professor of pediatrics at the Children’s Hospital of Philadelphia.
The meeting comes as vaccinations in the U.S. have flagged. About 229 million people, or 73% of the population aged 5 years and older, have completed a primary COVID-19 vaccine series, mostly with either Pfizer’s or Moderna’s products. But only 50.6 million have received a bivalent booster dose, which was authorized for most adults last August.
While COVID-19 cases and deaths remain at comparatively lower levels, some 45,000 people are testing positive and over 500 are dying each day in the U.S.
With COVID-19 here to stay, the FDA is planning for a future in which COVID-19 vaccination might look more like how influenza vaccines are annually updated. The agency foresees calling advisers to select target coronavirus strains in May or June each year, so drugmakers could update their shots in time for September vaccinations.
At Thursday’s meeting, executives from Pfizer and Moderna indicated that such a timeline could be met, although it’s not clear how much supply they’d be able to provide.
“We look forward to working with regulators on developing and implementing a streamlined plan for future vaccine updates as we aim to provide boosters that best match circulating strains,” Pfizer said in a statement after the meeting concluded.
In a separate statement, Novavax said it’s “prepared to deliver an updated vaccine following FDA guidance on strain change.”
Under the FDA’s plan, most adults would receive just one dose each fall, while certain young children, older adults and immunocompromised individuals would get two. The agency said it could still convene its advisers for ad hoc meetings if needed to respond to more worrisome variants that could emerge.
“The whole idea of this framework would be that for right now, barring some strain coming along that essentially breaks out of … immunity … we're proposing at least one meeting per year on strain selection and then possibly others,” said Peter Marks, head of the FDA office that reviews vaccines.
Yet some advisers cautioned that differences between the coronavirus and influenza could mean annual COVID-19 shots aren’t necessary in everyone to protect against severe disease. “We already have that with the original Wuhan vaccine,” said Offit, who’s argued that bivalent boosters are best suited for people at higher risk.
Another concern centered around whether the bivalent vaccines present any different safety risks, particularly in younger children and older adults.
The committee reviewed data on a possible link between Pfizer’s vaccine and strokes in people 65 years and older. The Centers for Disease Control and Prevention vaccine safety monitoring network, which includes major health systems in six states, identified an apparently higher risk in the first 21 days after a dose of Pfizer’s bivalent booster, compared to the following three weeks.
But, when compared to people who hadn't been boosted, the CDC’s analysis found no significant increased stroke risk. The FDA’s safety monitoring hasn’t picked up the same signal, either, although its data doesn’t include “transient ischemic attacks,” or temporary blockages that cause similar symptoms as strokes.
“The evidence is not sufficient to conclude that there is a safety problem with respect to stroke,” said Tom Shimabukuro, a CDC official, in a response to an adviser’s question Thursday.
Editor’s note: This story has been updated to include comment from Novavax.