RSV Immunization Coverage Among US Infants Receiving Nirsevimab or Maternal Vaccination

This observational report describes respiratory syncytial virus (RSV) immunization coverage among infants born in the United States from October 2023 through March 2024. The population included infants who received the nirsevimab monoclonal antibody or whose mothers received RSV vaccination during pregnancy. The study design was descriptive, and no comparator group was specified.

The report does not provide the sample size, specific coverage rates, absolute numbers, or statistical measures for the main outcome of RSV immunization coverage. No data on secondary outcomes, follow-up duration, or safety and tolerability of the interventions were reported. Adverse events, serious adverse events, and discontinuation rates were not described.

Key limitations include the absence of reported results, which prevents assessment of the actual immunization coverage achieved in this population. The lack of comparative data, safety information, and details on study methodology restricts interpretation. Funding sources and potential conflicts of interest were not reported.

For clinical practice, this report serves only as a preliminary acknowledgment that RSV immunization via these methods was being monitored in the specified US infant cohort during the 2023-2024 season. The absence of reported coverage rates means no conclusions can be drawn about the effectiveness or reach of these immunization strategies. Clinicians should await studies with complete outcome reporting to inform practice.