Review examines clesrovimab efficacy and evidence gaps in infant RSV prevention

A clinical perspective in Pediatric Research examines the role of clesrovimab (MK-1654; Enflonsia), a long-acting monoclonal antibody designed to provide season-long RSV protection after one dose. Informed by a narrative review, the article considers efficacy, safety and implementation alongside nirsevimab and maternal RSV vaccination. It notes that many severe RSV cases occur in previously healthy term infants, limiting the reach of prevention restricted to high-risk groups.

The authors cite the pivotal phase 2b/3 CLEVER trial in infants entering their first RSV season. Clesrovimab reduced RSV-associated medically attended lower respiratory tract infection and hospitalization, with a safety profile described as comparable to placebo. The reported absolute reduction in RSV hospitalization was approximately 1.9 percentage points, with an estimated number needed to treat of 51 over 150 days. The supplied preview does not provide the trial sample size or detailed safety results.

For clinical implementation, the perspective emphasizes timely administration, neonatal discharge planning, well-child care and coordination with maternal immunization programs. However, this is a narrative assessment rather than a new trial report. The authors identify no head-to-head comparisons with nirsevimab, limited post-licensure data and uncertainties about long-term effectiveness and affordability. Equitable access, sustained coverage and ongoing surveillance remain central implementation priorities.