The U.S. Food and Drug Administration has launched a safety review of two long-acting injectable drugs designed to protect infants and young children from respiratory syncytial virus (RSV), which hospitalizes thousands of American children annually.

The drugs, developed by Merck and Sanofi, are not vaccines but laboratory-made antibodies that help the immune system fight RSV. The review, described by a Health Secretary Robert F. Kennedy Jr. spokesman as routine, comes amid broader shifts in federal childhood vaccination recommendations. The FDA said it may update product labeling if warranted by available evidence.

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Merck and Sanofi emphasized they have not detected any new safety concerns. Merck’s injection, Enflonsia, is approved for babies before or during their first RSV season, while Sanofi’s Beyfortus has been studied in over 50 trials and administered to more than six million children worldwide.

RSV typically causes mild cold-like symptoms in healthy people but can be severe for infants and older adults. The CDC previously recommended these antibody treatments for newborns during RSV season and some 8- to 19-month-olds at higher risk.

Since taking office, Kennedy has replaced the CDC advisory panel and recently moved to end routine newborn hepatitis B vaccinations, sparking professional backlash. Meanwhile, the FDA continues to review vaccine safety, including COVID-19 shots, and considers updates to its longstanding approval processes.

Source: AP