RSV Vaccine Approved for Adults 18–59

FDA has approved a vaccine to prevent lower respiratory tract disease resulting from the respiratory syncytial virus (RSV) in adults 18 to 59 years of age who are at increased risk, Pfizer announced on Oct. 22, 2024. The bivalent RSV prefusion F vaccine, Abrysvo, has a broader indication to include those younger than 60 and is the only RSV vaccine approved in pregnant people who are at 32 through 36 weeks of gestation, and infants from birth to six months of age, according to the company (1).

“In the prefusion state, the RSV fusion protein (F) is a major target of neutralizing antibodies, serving as the basis of Pfizer’s RSV vaccine. Variations in the F protein sequence among RSV-A and RSV-B subgroups are clustered in a key antigenic site, a target for potent neutralizing antibodies,” stated the company (1).

According to Pfizer, FDA made its decision based on results from a Phase III clinical trial(NCT05842967), MONeT (RSV I M munizati ON Study for Adul T s at Higher Risk of Severe Illness), which looked at the safety and efficacy in adults with certain chronic medical conditions, such as asthma and diabetes.

“Immunocompromised adults, such as patients with cancer or autoimmune disorders, have a substantially increased risk of experiencing severe complications from RSV, yet there are currently no vaccines approved for those aged 18 to 59 in the [United States],” said Annaliesa Anderson, Pfizer senior vice president and chief scientific officer for vaccine research and development, in an August 2024 press release about the results (2). “We are encouraged by the positive top-line data from this study, which provide important evidence that Abrysvo has the potential to address a significant unmet need in this vulnerable population.”

“RSV represents a significant threat to younger adults with certain chronic conditions. After decades of vaccine research by the scientific community and Pfizer, we now have the opportunity to help alleviate the burden of RSV in this high-risk adult population,” said Aamir Malik, chief US commercial officer and executive vice president, Pfizer, in a press release (1). “With this approval, we are proud that Abrysvo is now the only RSV vaccine indicated for adults aged 18 to 49 at increased risk for the disease, expanding on its existing indications for older adults and pregnant women.”

Abrysvo was also granted marketing authorization in the European Union by the European Commission in August 2023 for older adults and maternal immunization (3).

“The approval of ABRYSVO in Europe marks significant progress in the scientific community's efforts to provide meaningful protection against RSV, a common respiratory virus that could potentially be severe and even life-threatening, especially for infants and older adults,” said Anderson, at the time (3). “Last year’s significant number of newborns, children, and adults being hospitalized across Europe demonstrated the immense need for protection against severe RSV cases. The approval of the vaccine for both older adults and infants through maternal immunization is a triumph for public health and we hope to see a tremendous impact for future seasons.”

References

1. Pfizer.U.S. FDA Approves Pfizer’s RSV Vaccine Abrysvo for Adults Aged 18 to 59 at Increased Risk for Disease. Press Release. Oct. 22, 2024.
2. Pfizer. Pfizer Announces Top-Line Results of Abrysvo for RSV in Immunocompromised Adults. Press Release. Aug. 12, 2024.
3. Pfizer. European Commission Approves Pfizer’s Abrysvo to Help Protect Infants through Maternal Immunization and Older Adults from RSV. Press Release. Aug. 24, 2023.