A new study in JAMA Pediatrics confirms that nirsevimab significantly cuts hospital admissions for respiratory syncytial virus in infants, offering promising real-world support for targeted prophylaxis during peak seasons.
A new real-world study in JAMA Pediatrics suggests that nirsevimab, the long-acting monoclonal antibody used to protect infants against respiratory syncytial virus, was linked to fewer hospital admissions for RSV-related lower respiratory tract infections in the first year after treatment. The effect was seen across the 2023-24 and 2024-25 RSV seasons, offering early evidence outside the clinical trial setting that the preventive treatment can reduce severe illness in young children.
RSV is a common cause of bronchiolitis and pneumonia in babies and can become dangerous quickly, particularly in premature infants and children with underlying health problems. Nirsevimab works differently from a vaccine: it gives passive immunity by supplying ready-made antibodies that attach to a key RSV protein, helping block infection and limit viral spread. The study’s findings fit with a wider body of recent research. A modelling analysis published in 2026 estimated that higher nirsevimab coverage during the 2024-25 US season could prevent tens of thousands of medically attended RSV illnesses and hospitalisations, while a population study in northern Italy found a sharp fall in RSV admissions after seasonal use of the antibody.
The JAMA Pediatrics researchers looked at hospital patterns in children who received nirsevimab and compared them with those who did not. They found no comparable reduction in admissions for non-RSV infections, which strengthens the case that the benefit was specific to RSV rather than to broader differences in care or illness trends. The study also did not find evidence of fewer asthma-related hospitalisations, an important distinction given that RSV has been linked to later respiratory problems but cannot be assumed to prevent them.
The protective effect was strongest in the first year and was not clearly seen in the second. That is not unexpected, since nirsevimab is designed to cover a single RSV season rather than provide long-term protection. Other recent studies have reached broadly similar conclusions: a 2025 cohort study reported lower RSV hospitalisation risk in infants during the 2024-25 season, a multicentre observational study found fewer paediatric RSV admissions and fewer intensive care cases after implementation, and surveillance research suggested that both maternal RSV vaccination and nirsevimab helped cut hospitalisations in US infants. Together, the findings point to a growing consensus that targeted infant prophylaxis can substantially ease the burden of RSV when coverage is high.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
