Nirsevimab showed 74.5 percent efficacy against medically attended lower respiratory tract infections caused by a respiratory syncytial virus (RSV) in healthy infants, according to an international, randomized, placebo-controlled Phase 3 clinical trial. It is the first potential immunization against RSV in the general infant population, with a single dose providing safe protection across the entire RSV season. Results were published in the New England Journal of Medicine.
RSV is a common contagious virus that causes seasonal epidemics of lower respiratory tract infections, leading to bronchiolitis and pneumonia in infants. Lurie Children’s was among the highest US sites in the trial.
A separate Phase 2/3 trial, also published in the New England Journal of Medicine, evaluated the safety of nirsevimab in infants with congenital heart disease, chronic lung disease, and prematurity entering their first RSV season nirsevimab had similar safety and tolerability profile compared to palivizumab. Results in this population of infants indicated similar protection against RSV to healthy term and late preterm infants.