U.S. F.D.A. advisers recommend updated boosters that target Omicron variants

Covid Live Updates: F.D.A. Panel Recommends Updated Boosters That Target Forms of Omicron The move came as new federal estimates show two subvariants, known as BA.4 and BA.5, make up more than half of new U.S. cases in the country. But it is possible that the virus might evolve yet again by the fall. The New York Times

An expert committee recommended Tuesday that the Food and Drug Administration plan on an updated booster shot of the coronavirus vaccines that targets some form of the Omicron variant that has dominated for months.

The panel’s 19-2 vote paves the way for F.D.A. regulators to authorize a new formulation for the boosters that the Biden administration hopes to offer later this year, before an expected winter resurgence of the virus.

The committee debated but did not specify which formulation might work best. The F.D.A. appeared to be leaning toward a combination of the existing vaccine and two subvariants of Omicron, known as BA.4 and BA.5. According to new estimates from the Centers for Disease Control and Prevention, those two subvariants together now make up more than half of new cases in the country.

Dr. Peter Marks, who oversees the F.D.A.’s vaccine division, displayed a timeline suggesting that regulators would decide on a new vaccine composition by early July, and that a fall booster campaign could begin in October. Manufacturers of the mRNA vaccines, made by Moderna and Pfizer-BioNTech, require roughly three months to begin producing doses with a new composition.

Clinical trial results on a combination of the so-called “prototype,” or existing, vaccines and Omicron itself have received mixed reviews so far. In briefing materials, regulators suggested that such a design is “already somewhat outdated.”

The panel struggled with what one member called “trying to predict the future” of where the virus is headed. Another panelist called the data “uncomfortably scant.”

Dr. Adam C. Berger, a National Institutes of Health official, said he supported an updated booster in theory, “but I’m not sure that we have evidence to support a change necessarily today.” Other members said the most impressive booster might be one proposed by Novavax, a company whose vaccine is not yet even available as initial doses in the United States.

But more members of the panel seemed convinced that an updated booster was needed. “We’re all troubled by the steady erosion of immune protection,” Dr. Mark Sawyer, an infectious disease specialist at Rady Children’s Hospital in San Diego, said. “We’re going to be behind the eight ball if we wait longer.”

The panel seemed generally against switching the vaccine formulation for people who have not yet been fully vaccinated.

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