Lessons from implementing a long-acting monoclonal antibody (nirsevimab) for RSV in France, Spain and the US

Respiratory syncytial virus (RSV) is a leading cause of serious respiratory illness and hospitalisation in infants. While infants who were born prematurely or with certain health conditions are at increased risk of severe illness from RSV, most of the infants who become seriously unwell with the virus are otherwise healthy and born at term. A new preventive monoclonal antibody (nirsevimab), which offers protection from severe RSV for at least 150 days and has been shown to significantly reduce hospitalisation, has been approved and recommended for all infants in many countries. Given that nirsevimab is used as a passive immunising agent, and that it may be given in hospitals or outpatient settings, health system leaders need to carefully consider how it will be implemented and ensure their health systems are ready to do so. In this article, we discuss key lessons learnt from the implementation of nirsevimab in France, Spain and the US in 2023, based on the available published evidence and the authors’ own experiences and perspectives. These learnings may be helpful for health system leaders in other countries who are preparing to implement similar programmes.