Real-world evidence on nirsevimab in pediatric populations: a systematic review

ABSTRACT

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections in infants, with a substantial burden of hospitalizations, intensive care admissions, and healthcare costs worldwide. Nirsevimab, a long-acting monoclonal antibody targeting the RSV prefusion F protein, demonstrated high efficacy and a favorable safety profile in randomized clinical trials and has since been incorporated into national RSV prevention programs in several countries. This systematic review synthesizes the available real-world evidence on the effectiveness and safety of nirsevimab in pediatric populations. The review was conducted according to PRISMA 2020 guidelines, searching PubMed/MEDLINE, Embase, Web of Science, and Scopus, supplemented by grey literature. Observational real-world studies enrolling infants and children aged ≤24 months who received nirsevimab were included. Risk of bias was appraised with the Newcastle–Ottawa Scale and certainty of evidence with GRADE; findings were synthesized narratively. Fifty-four studies from nine countries were included. Nirsevimab was consistently associated with substantial reductions in RSV-related hospitalizations, emergency department visits, and ICU admissions, with protection observed in both general and high-risk infant populations. Although less frequently reported, adverse events were uncommon, mostly mild and transient, with no unexpected safety signals. Certainty of evidence was moderate for RSV-related hospitalization and ICU admission, and low or very low for other outcomes. Current real-world evidence shows that nirsevimab is an effective and well-tolerated strategy for preventing RSV disease in infants and young children, consistent with the pivotal trials and supporting its role in immunization programs. Continued surveillance is needed to monitor long-term effectiveness and safety.

IMPACT STATEMENT
Real-world evidence from nine countries shows that nirsevimab substantially lowers infant hospitalizations and intensive care admissions for respiratory syncytial virus, supporting its role in national immunization programs and routine practice.

Key words
Nirsevimab; respiratory syncytial virus; real-world evidence; infant; immunization.