FDA reviews safety of approved RSV antibodies for infants

The FDA has begun a rigorous safety review of monoclonal antibody products used to prevent respiratory syncytial virus (RSV) in infants, according to reports citing FDA statements.2

The review focuses on approved RSV antibodies for infants, including Sanofi and AstraZeneca’s nirsevimab (Beyfortus) and Merck’s investigational or early-use RSV antibody products for young children.23

Regulators are re‑examining post-marketing safety data and real‑world use to assess rare but potentially serious adverse events in infants receiving these antibodies.23

Sanofi and AstraZeneca report that the safety and effectiveness of Beyfortus have been demonstrated in more than 50 clinical and real‑world studies, supporting its existing approval for RSV prevention in infants.3

The current FDA action is described as a re‑evaluation and intensified monitoring, not a withdrawal of authorization; the products remain available while data are being reviewed.23

This review comes amid broader ongoing FDA and CDC safety surveillance of RSV preventives, which already includes vaccines and antibodies tracked through systems such as VAERS, V-safe, and other post‑licensure studies.1

Sources:

1. https://www.cdc.gov/vaccine-safety/vaccines/rsv.html

2. https://firstwordpharma.com/story/6737168

3. https://www.fiercepharma.com/pharma/fda-now-has-merck-az-and-sanofi-rsv-shots-infants-its-crosshairs-reuters