CDC Advisors Narrow RSV Vaccination Guidelines

In an unexpected move, the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices (ACIP) has altered the guidelines for respiratory syncytial virus (RSV) vaccinations, potentially affecting a smaller segment of the population. This decision arrives as the RSV vaccine market, which has recently seen the arrival of Moderna’s mRESVIA, faces potential contraction.

For what will be only the second RSV season with available vaccines, the ACIP panel unanimously recommended that adults aged 75 years and older, as well as those aged 60 to 74 with increased risk due to underlying medical conditions, receive a single lifetime dose of the RSV vaccine. This is a significant change from the previous guidance, which recommended vaccination for all adults aged 60 and older, following consultation with their healthcare providers. For the 75-and-above group, the recommendation now applies automatically, bypassing the need for medical evaluation. However, the restriction for the 60-to-74 age group represents a clear setback for vaccine manufacturers.

The revision was influenced by a possible link between the RSV shots and Guillain-Barré syndrome (GBS), a rare neurological disorder. Earlier this year, health officials noted preliminary findings that 23 out of approximately 9.5 million older adults who received an RSV vaccine developed GBS. This connection is still under investigation, with GSK committing to a controlled epidemiological study initiated in March.

Following the ACIP vote, share prices for the major RSV vaccine makers dropped significantly. GSK’s shares fell by 3.57%, Pfizer’s by 2.04%, and Moderna’s by a substantial 11%, all by market close on Wednesday.

Moderna is already facing a challenging path to compete with the more established vaccines, GSK’s Arexvy and Pfizer’s Abrysvo. Arexvy was the first RSV vaccine to receive approval last year and has since dominated the market, capturing approximately two-thirds of the market share and generating 182 million pounds sterling ($227 million) in revenue during the first quarter of this year. In comparison, Pfizer’s Abrysvo brought in $145 million in the same period.

The recent ACIP meeting was crucial for assessing the potential impact of Moderna’s entry into the market, according to GSK’s Luke Miels. The decision marks the start of a competitive phase to secure contracts ahead of the upcoming RSV season, which typically begins in the fall.

While Moderna’s vaccine has not yet been launched, the long-term data presented at the ACIP meeting indicates a tough competition ahead. At 18.8 months of follow-up, mRESVIA’s vaccine efficacy rate was 50%, as reported by the mRNA drugmaker. This contrasts with an earlier phase 3 study, which had shown an 81% efficacy rate against RSV after 3.7 months of follow-up. On the other hand, Abrysvo’s efficacy rate was 78% at 16.4 months, and Arexvy’s was 68% after 23 months.

Arexvy’s latest data, which suggest it has “the most impressive” vaccine efficacy among the group, should help it maintain its majority market share, according to analysts at Evercore ISI. However, the preference for GSK’s vaccine is not universal. Recently, the U.K. government selected Pfizer to supply 5 million doses of Abrysvo over the next two years. Moreover, Abrysvo is also sanctioned for maternal vaccination, offering protection for newborns.

In summary, the revised RSV vaccination guidelines from ACIP could significantly impact the market dynamics for the three major vaccine manufacturers. With new data and shifting recommendations, the competition among GSK, Pfizer, and Moderna is set to intensify as they prepare for the next RSV season.