Nirsevimab reduces RSV-related outcomes in infants

Immunoprophylaxis with nirsevimab results in a 74-percent decrease in hospitalization and 85-percent reduction in paediatric intensive care unit (PICU) admissions due to respiratory syncytial virus (RSV)-related bronchiolitis, a study has shown.

A total of 15,341 infants were included in this retrospective cohort study. A dose of nirsevimab led to significant reductions in hospital admission (adjusted hazard ratio [aHR], 0.26, 95 percent confidence interval [CI], 0.17–0.39), PICU admission (aHR, 0.15, 95 percent CI, 0.07–0.28), and emergency visits (aHR, 0.46, 95 percent CI, 0.23–0.90) due to RSV bronchiolitis.

For all-cause bronchiolitis, the corresponding aHRs were 0.45 (95 percent CI, 0.31–0.63), 0.23 (95 percent CI, 0.13–0.41), and 0.49 (95 percent CI, 0.35–0.68).

"These percentages are slightly lower than those for the catch-up cohort,” the authors said. “This information may help the implementation of RSV-immunization campaigns by public health authorities.”

This study included infants born between 1 October 2023 and 21 January 2024 in Catalonia, Spain, according to their immunization with nirsevimab (immunized and nonimmunized). The authors followed individuals until the earliest of an outcome (hospital emergency visits, hospital admission, or PICU admission), death, or the end of the study.

Kaplan-Meier estimator and Cox regression models were used to estimate HRs and 95 percent CIs. Sensitivity analysis was also carried out through matching.

“In Catalonia, infants <6 months old were eligible to receive nirsevimab, a novel monoclonal antibody against RSV,” the authors said.