The CDC’s Advisory Committee on Immunization Practices (ACIP) has blessed Merck’s new respiratory syncytial virus (RSV) shot Enflonsia, but the decision was hardly resounding from Robert F. Kennedy Jr.’s newly formed panel of advisors.
The ACIP signed off on recommending Merck’s newly approved monoclonal antibody by a vote of 5 to 2. The committee endorses one dose of Enflonsia to be given to infants younger than 8 months of age who are born during or entering their first RSV season and who are not already protected by a maternal vaccine.
The vote helps relieve concerns that the new panel—which was assembled by Health and Human Services (HHS) Secretary Kennedy after he dismissed the group’s previous 17 members early this month—would reflect Kennedy’s long-held anti-vaccine beliefs. Importantly, Merck's new product is not a vaccine, but rather an antibody used prophylactically to help protect against RSV.
While ACIP recommendations are generally rubber-stamped, they can be overturned after review by the CDC. Acting Director Susan Monarez, Ph.D., has been nominated by President Donald Trump after his initial choice for the post, Dave Weldon, M.D., was pulled over pushback over his controversial stance on vaccines.
The new recommendation for Enflonsia, which was approved by the FDA just two weeks ago, matches that of Sanofi and AstraZeneca’s Beyfortus, which has been on the market for the last two years and generated sales of $1.8 billion in 2024.
"The Committee’s recommendations are an important step forward in efforts to help reduce the significant burden RSV continues to place on infants, families, and health care systems," Richard M. Haupt, Merck's head of global medical & scientific affairs, vaccines and infectious diseases, said in a statement.
Before Thursday’s vote, committee member Retsef Levi, Ph.D., raised several concerns about the deaths in clinical trials of babies who had received Enflonsia or Beyfortus. Most of the issues raised by Levi were addressed by representatives from Merck and from others on the committee.
The appointment of Levi, who is a business professor at MIT, was controversial as he has been an outspoken critic of COVID-19 vaccines.
Another controversial new committee member, Robert Malone, M.D., who has suggested that mRNA COVID vaccines can cause cancer and has served as an expert witness testifying against Merck’s Gardasil vaccine, voted in favor of the recommendation of Enflonsia.
The other dissenting vote came from Vicky Pebsworth, Ph.D., who voiced discomfort over adding another new shot to the combination of vaccines commonly given to children in the U.S.