CDC Panel Recommends Expanded Use of RSV Vaccines, Holds Off on Boosters

In a significant development for the respiratory syncytial virus (RSV) vaccine market, a panel of advisers to the Centers for Disease Control and Prevention (CDC) has recommended broadening the eligible age range for RSV vaccination. However, the committee stopped short of endorsing booster shots, citing a lack of clear evidence on their efficacy.

Expanded Age Range for RSV Vaccination

The CDC's Advisory Committee on Immunization Practices (ACIP) voted nearly unanimously to recommend RSV vaccination for adults aged 50 to 59 who are at higher risk of severe RSV-related disease. This expansion builds upon the current guidance, which suggests vaccination for all individuals 75 and older, as well as high-risk adults between 60 and 74 years of age.

If adopted by the CDC, this recommendation would immediately benefit pharmaceutical giants GSK and Pfizer, both of which have RSV vaccines approved for use in people under 60. Moderna could also stand to gain from this decision, as the Food and Drug Administration (FDA) is expected to consider approval for its RSV vaccine in this age group later this year.

Booster Shots and Ongoing Research

Despite the expanded age recommendation, the committee did not endorse booster shots or vaccination for younger adults. CDC panelists noted that clinical testing has not definitively shown that an additional dose can improve protection against the disease. While antibody levels do increase after revaccination, they do not reach the same heights as after the initial dose.

Michael Melgar, co-lead of the work group for RSV in adults for the ACIP, explained, "There remains important uncertainty in whether revaccination can restore protection to levels seen after the first dose, and this may be more important when developing a recommendation for younger adults who have longer remaining life expectancy."

The committee plans to discuss revaccination at a meeting in June. In the meantime, the lack of endorsement for boosters "remains a major overhang to the market potential" of RSV shots, according to William Blair analyst Myles Minter.

Safety Considerations and Market Impact

The committee also highlighted the risk of Guillain-Barré syndrome, a rare neurological side effect that was added to the prescribing information for Pfizer's Abrysvo and GSK's Arexvy last year. This safety concern, along with the uncertainty surrounding booster shots, may impact the market potential of these vaccines.

The news of the committee's recommendations had a slight negative impact on the stock prices of Pfizer, GSK, and Moderna, all of which experienced minor dips following the announcement.

As the pharmaceutical industry awaits the CDC's final decision on these recommendations, the expanded age range for RSV vaccination represents a potential growth opportunity for vaccine manufacturers, while the hesitancy on boosters underscores the need for continued research and data collection in this evolving field.