Kennedy Expands RSV Vaccine Recommendations. Moderna, Pfizer Shares Are Up.

Moderna released its vaccine for RSV, mRESVIA, last year. (Adam Glanzman/Bloomberg)

Health Secretary Robert F. Kennedy Jr. signed off last week on an expansion to the Centers for Disease Control and Prevention’s recommendations for who should receive a respiratory syncytial virus vaccine, the agency said Wednesday.

The CDC’s vaccines advisory committee, called the Advisory Committee on Immunization Practices, voted for the expanded recommendation at a meeting in April. Kennedy, a prominent vaccine skeptic, has since fired all the members who sat on the committee at the time, leaving the fate of their pending recommendations uncertain.

With no fanfare or press announcement, the CDC updated its website Wednesday to say that Kennedy had approved the fired members’ expanded RSV recommendation in late June. He also approved tweaks to their recommendations for meningococcal and chikungunya vaccines.

It is generally the role of the CDC director to accept or reject the decisions of the vaccines advisory committee. There is currently no CDC director—so Kennedy made the decisions.

The new guidance is a relatively minor tweak. It recommends RSV vaccine s for people aged 50 to 59 who are at high risk of severe RSV disease. Previously, the CDC recommended the vaccine for all adults aged 75 and up, and for high risk adults aged 60 to 74.

The CDC still recommends only a single dose of an RSV vaccine for all groups, and no booster shots.

The expanded recommendation is good news for Moderna, Pfizer, and GSK, which all sell RSV vaccines for older adults. Moderna shares were up 5.9% on Wednesday, while Pfizer was up 1%. GSK’s American depositary receipt was down 1%.

Kennedy’s approval of the expanded recommendation introduces a wrinkle into his takeover of the U.S. public-health apparatus. Last week, at the vaccine committee’s first meeting since Kennedy replaced its members, it handed a victory to the antivaccine movement: In a largely symbolic vote, the committee recommended against any further use of the preservative thimerosal in flu vaccines.

RSV vaccines aren’t a hot-button issue, nor have they been a focus of the antivaccine movement. But the expansion of the vaccines’ recommendations highlights how, in some ways, vaccine regulation is continuing as normal, even amid Kennedy’s disruptions.

The market for RSV vaccines started off hot two years ago, when the CDC set broad recommendations for who should get the shot: Anyone aged 60 and up was eligible upon consultation with their doctor. It became more challenging after the agency narrowed its recommendations in 2024.

Sales of GSK’s RSV shot Arexvy were $1.6 billion in 2023, its debut year, but fell to $739 million in 2024. Sales of Pfizer’s Abrysvo, which is also approved for pregnant women to prevent RSV in their infants, fell from $890 million in 2023 to $755 million in 2024.

Sales for Moderna, which launched its RSV shot mRESVIA in 2024, were even more disappointing last year, at just $25 million.

Write to Josh Nathan-Kazis at josh.nathan-kazis@barrons.com