Analysis suggests nirsevimab reduces infant RSV hospitalizations by 83%

A national Australian hospital surveillance study published in Eurosurveillance reported that nirsevimab was associated with an 83.1% reduction in RSV-related hospitalizations among infants under 12 months in jurisdictions using population-wide programs during 2024; Western Australia and Queensland had notably lower total case counts than other states.

An Australian hospital-based surveillance study found lower RSV-related hospitalizations among infants after use of nirsevimab during the 2024 season. The analysis, published in Eurosurveillance, used data from 22 hospitals collected April–December 2024. Researchers examined nearly 4,000 hospitalized patients with RSV; infants under 12 months made up nearly 40% of cases. Severe disease was reported more often in infants born prematurely, those with cardiac or neurologic conditions or genetic or metabolic disorders, and First Nations children. Key findings: - The analysis covered 22 hospitals in Australia from April to December 2024 and included nearly 4,000 hospitalized children and adults with RSV. - Infants under 12 months accounted for nearly 40% of hospitalized cases. - In jurisdictions with population-wide nirsevimab programs (Western Australia and Queensland), effectiveness against RSV hospitalization in infants under 12 months was reported as 83.1%. - Western Australia recorded about a 50% reduction in hospitalized RSV cases among infants younger than 12 months; Queensland saw a similar reduction for infants aged 6 months and under. - Total RSV cases in Western Australia and Queensland were significantly lower than in the rest of the country. - The authors noted limitations, including some self-reported information and possible underreporting of immunization status. Summary: The authors wrote that the data demonstrate the effectiveness of nirsevimab in jurisdictions providing population-wide programs in 2024, with lower infant hospitalization counts reported in Western Australia and Queensland. Undetermined at this time.