FDA Launches Safety Review of Injectable RSV Treatments for Infants

Wed Dec 10 2025 04:59:14 GMT+0200 (Eastern European Standard Time)

The FDA has initiated a safety review of two new injectable drugs designed to protect babies and toddlers from the respiratory syncytial virus (RSV), following concerns about their use amid changes in vaccination recommendations.

The Food and Drug Administration (FDA) is currently reviewing the safety of two injectable treatments for RSV, a virus that poses serious health risks to infants and young children. These medications, developed by Merck and Sanofi, aim to enhance the immune system's ability to combat RSV. Although the companies report no new safety concerns associated with their products, this review coincides with broader changes in childhood vaccination recommendations under the leadership of Health Secretary Robert F. Kennedy Jr. Both drugmakers affirm their commitment to transparency and are cooperating with the FDA's evaluation.

WASHINGTON (RTWNews) — The Food and Drug Administration (FDA) has launched a safety review of two injectable drugs aimed at protecting infants and toddlers from respiratory syncytial virus (RSV), which is responsible for sending thousands of American children to the hospital each year.

The injectable treatments developed by Merck and Sanofi are not classified as vaccines, but their review is underway amidst significant changes to routine vaccination recommendations, spearheaded by Health Secretary Robert F. Kennedy Jr. A spokesperson for Kennedy has characterized the review as a standard safety evaluation, noting that the FDA will make necessary updates to product labeling should the evidence justify such action.

In separate statements, Merck and Sanofi maintained that they have not identified any new safety signals associated with their drugs, which have been approved to help infants and children at risk of severe RSV infection.

These treatments consist of laboratory-engineered versions of natural antibodies that bolster the immune response against RSV, a virus that typically causes only mild respiratory illness but can be life-threatening for vulnerable populations. The FDA has approved RSV vaccines for older adults and pregnant women, but not yet for infants, making these injections a pivotal defense against the virus in young children.

Following the announcement of the safety review, both companies noted that they are dedicated to transparency and cooperation with regulatory processes. Merck's Enflonsia is specifically designed to protect infants during their crucial first RSV season, which can last about five months. A Sanofi representative confirmed that they continuously submit any potential safety concerns to the FDA, having conducted over 50 studies without discovering new safety issues.

While RSV infections can be relatively innocuous for most healthy individuals, they pose grave risks to young children and the elderly. Recently, the Centers for Disease Control and Prevention (CDC) recommended that these antibody shots be administered to newborns, particularly if mothers were not vaccinated during pregnancy. The revised vaccination guidelines have stirred controversy, particularly after significant changes in the CDC committee under Kennedy's administration.

In tandem with investigating RSV therapies, the FDA has also faced scrutiny regarding its vaccine safety measures, particularly concerning COVID-19 vaccines, prompting calls for a comprehensive overhaul of its longstanding vaccine approval processes.