FDA Initiates Safety Review of Infant RSV Drugs Beyfortus and Enflonsia Amid Kennedy Administration Scrutiny
Key Insights
The FDA has launched a safety review of two approved RSV (search) monoclonal antibody drugs for infants, Beyfortus from Sanofi/AstraZeneca and Enflonsia (search) from Merck (search), despite no reported safety issues.
Both drugs are monoclonal antibodies that provide passive immunization against respiratory syncytial virus (search) and are recommended by the CDC (search) for infants under 8 months during RSV (search) season.
The review comes under Health Secretary Robert F. Kennedy Jr.'s administration, which has been scrutinizing immunizations, including recently rolling back hepatitis B (search) vaccine recommendations for newborns.
The Food and Drug Administration has launched a safety review of two approved RSV (search) drugs for infants, marking the latest immunizations to face scrutiny under Health Secretary Robert F. Kennedy Jr.'s administration. The review targets Beyfortus, developed by Sanofi and AstraZeneca, and Enflonsia (search) from Merck (search), despite no reported safety issues with either respiratory syncytial virus (search) treatment.
FDA Review Details
Andrew Nixon, a spokesperson at the Department of Health and Human Services, confirmed that the FDA is "rigorously reviewing the available data, as it does for all products, to ensure decisions remain rooted in evidence-based science and in the best interest of patients." The agency stated it "routinely evaluates emerging safety information and will update product labeling if warranted by the totality of the evidence."
The review's scope and potential outcomes remain unclear, with possibilities ranging from product label changes to restrictions on availability. Reuters first reported the FDA's safety review initiative.
Drug Safety Profiles and Clinical Evidence
Both drugs are monoclonal antibodies that function similarly to vaccines but deliver antibodies directly into the body through passive immunization rather than prompting the immune system to produce its own antibodies.
A Sanofi spokesperson emphasized that Beyfortus's safety and effectiveness has been demonstrated across more than 50 clinical studies and real-world studies involving over 400,000 infants. "At this time, no safety issue has been identified from clinical studies of nirsevimab or from post-marketing experience with more than six million babies immunized worldwide," the spokesperson stated, using the drug's generic name.
Merck (search) representatives noted that the safety standards for vaccines and preventive therapies like Enflonsia (search) are "exceptionally, and appropriately, high." The company confirmed meeting with FDA representatives and welcomed "ongoing scientific exchange and dialogue with the FDA and other regulatory or health authorities."
Current Recommendations and Usage
The CDC (search) currently recommends either product for infants under 8 months born during or entering their first RSV (search) season. For older infants at increased risk, only Beyfortus receives recommendation. Both drugs are included in the CDC's childhood immunization schedule.
Medical Community Response
Dr. Sean O'Leary, a pediatric infectious disease expert and spokesman for the American Academy of Pediatrics, expressed concern that the review aims to "sow distrust" in immunizations. "I certainly hope nothing regulatory comes of this, because there's no basis for it," O'Leary said. "But even if it doesn't, this systematic attempt to dismantle our immunization infrastructure is causing real harm in real time, in creating confusion among parents and even among clinicians."
O'Leary warned that rolling back access to RSV (search) injections would "inevitably lead to fewer children receiving the monoclonal antibody and more kids getting hospitalized."
RSV Disease Burden
Respiratory syncytial virus (search) poses significant health risks to infants, with roughly two to three of every 100 infants under 6 months hospitalized with RSV (search) annually, according to CDC (search) data. While most RSV cases cause mild, cold-like symptoms, the virus can also cause severe illness, including pneumonia (search) and bronchiolitis (search), a lung infection that impairs breathing.
Current CDC (search) surveillance indicates that RSV (search) cases are beginning to increase in parts of the United States. O'Leary noted that the drugs "have been shown to be very safe in clinical trials" and that their broad implementation has resulted in "really profound impacts on hospitalizations for young children."
Broader Policy Context
The RSV (search) drug review occurs alongside other immunization policy changes under Kennedy's leadership. On Friday, a CDC (search) vaccine advisory group selected by Kennedy voted to rollback a decades-long recommendation requiring all newborns to receive hepatitis B (search) vaccine within 24 hours of birth, a decision that major medical organizations criticized.