Safety of Nirsevimab for RSV in Infants with Heart or Lung Disease or Prematurity

This correspondence reports on the safety and pharmacokinetics of nirsevimab, a monoclonal antibody for preventing respiratory syncytial virus (RSV) infections, in high risk infants including preterm infants and those with congenital heart disease (CHD) or chronic lung disease (CLD). The study compared a single dose of nirsevimab (50 mg for infants <5 kg; 100 mg for ≥5 kg) with monthly palivizumab (15 mg/kg) in 925 infants across two cohorts. Results demonstrated comparable safety profiles between treatments, with no treatment-related serious adverse events. Adverse events of special interest were rare (0.2–0.5%), and medically attended RSV infections occurred in 0.6% of nirsevimab recipients versus 1.0% with palivizumab. Serum nirsevimab levels and low antidrug antibody responses (0.4%) supported its pharmacokinetic suitability. The findings suggest nirsevimab as a safe, effective single-dose alternative to palivizumab for RSV prophylaxis in high risk infants.

This correspondence reports on the safety and pharmacokinetics of nirsevimab, a monoclonal antibody for preventing respiratory syncytial virus (RSV) infections, in high risk infants including preterm infants and those with congenital heart disease (CHD) or chronic lung disease (CLD). The study compared a single dose of nirsevimab (50 mg for infants <5 kg; 100 mg for ≥5 kg) with monthly palivizumab (15 mg/kg) in 925 infants across two cohorts. Results demonstrated comparable safety profiles between treatments, with no treatment-related serious adverse events. Adverse events of special interest were rare (0.2–0.5%), and medically attended RSV infections occurred in 0.6% of nirsevimab recipients versus 1.0% with palivizumab. Serum nirsevimab levels and low antidrug antibody responses (0.4%) supported its pharmacokinetic suitability. The findings suggest nirsevimab as a safe, effective single-dose alternative to palivizumab for RSV prophylaxis in high risk infants.