12/05/2025
Respiratory syncytial virus (RSV) immunization nirsevimab is 80% effective against intensive care unit (ICU) admission, according to a new study. RSV is a leading cause of ICU admission for infants. Researchers set out to look at how well nirsevimab can protect them. The study, "Nirsevimab Effectiveness Against Intensive Care Unit Admission for Respiratory Syncytial Virus in Infants — 24 States, December 2024–April 2025," used data from patients younger than 1 year admitted to one of 27 pediatric ICUs from Dec. 1, 2024, to April 15, 2025. The authors compared 457 infants with a positive RSV test to 302 infants with respiratory symptoms who tested negative for RSV. About 14% of those who tested positive had received nirsevimab compared to 45% of those who tested negative. Nirsevimab was 80% effective against RSV-associated ICU admission. Effectiveness was higher at 7-59 days (86%) than at 60-183 days (66%). The immunization also was 83% effective against acute respiratory failure. Learn more in AAP News:
The AAP recommends RSV immunization with nirsevimab or clesrovimab for infants under 8 months of age born during or entering their first RSV season if their pregnant parent was not vaccinated during that pregnancy.