New long‐acting monoclonal antibody reduces RSV infections in healthy preterm infants

Abstract

The monoclonal antibody (mAb) palivizumab is currently the only agent available proven to reduce the incidence of severe respiratory syncytial virus (RSV) disease in high-risk children, but its uptake is low, primarily due to unclear cost effectiveness and impractical monthly dosing requirement. A randomised controlled trial of an extended half-life, RSVspecific mAb, nirsevimab, showed it was safe and efficacious in preterm infants (29–34 weeks gestation). The study randomised 1453 infants to receive a single, pre-RSV-season dose of nirsevimab or placebo. A single dose of nirsevimab resulted in a 70.1% (95% confidence interval: 52.3–81.2) lower incidence of medically attended RSV-associated acute lower respiratory infection (ALRI) and a 78.4% (95% confidence interval: 51.9–90.3) lower incidence of RSV-associated hospitalisation compared with the control group. This equates to a number needed to treat of 14.5 infants to avoid one RSV-associated ALRI and 30.3 infants to avoid one RSV-associated hospitalisation. Nirsevimab is currently being investigated in Phase 3 trials enrolling healthy late-preterm and full-term infants. This single dose mAb presents a new, more feasible possibility for RSV protection in infants. Time will tell regarding its safety and efficacy in other riskgroups, and whether it will be priced to be cost-effective for widespread use and accessible beyond high income country settings.