Until last year, there were no widespread prevention strategies for respiratory syncytial virus (RSV), which is the leading causes of bronchiolitis in children, resulting in millions of pediatric intensive care unit (PICU) stays each year.
Last year, a prenatal maternal vaccine (Avrexy) and a long-lasting monoclonal antibody called nirsevimab were approved for use in the United States. Both products are meant to provide passive immunity to babies against RSV, with nirsevimab approved through the second year of life for children at high risk of complications from RSV.
Nirsevimab and Avrexy were shown to be 83% and 67% effective at preventing hospitalization, respectively, in trials.
In a new study published in JAMA Network Open, authors estimate how impactful these treatments could be in reducing the total number of PICU hospitalizations annually.
The authors based their estimates on US pediatric ICU encounters with and without RSV from January 1, 2017, to June 1, 2023. In total 11, 782 ICU encounters from 53 hospitals were included in the analysis. The average patient age was 4.5 years, and the average length of stay was 1.8 (1.0 to 3.9) days
About 11% of visits (13,702) were due to RSV, accounting for 21.1% of the total ICU days. Of the 13,702 visits with RSV, 5,217 (38.6%) would have been eligible for RSV prevention. When looking at children age 2 and under, RSV accounted for 16.6% of hospitalizations.
Potential 4.4% reduction in ICU encounters
Using a 75% combined efficacy to represent both nirsevimab (83.2% efficacy) and Avrexy vaccine (63.7% efficacy) at preventing hospital admission, and a nationwide 65% to 85% uptake of maternal vaccines or infant antibodies, the authors estimated 4.4% of ICU encounters and 9.2% of ICU days represent encounters that have RSV and are now eligible for RSV prevention.
The results suggest that efforts to increase availability and acceptance of these therapies are warranted.
"The results suggest that efforts to increase availability and acceptance of these therapies are warranted,” the authors wrote.
In a commentary on the study, two Spanish researchers said the study’s findings "support the mounting evidence that the recently licensed RSV preventive strategies may substantially change the epidemiology of RSV bronchiolitis and associated health care system utilization as we currently know it.
"The upcoming respiratory seasons need to be closely surveilled, and pertinent analyses conducted, to allow setting-specific evidence-based policy decision-making regarding which RSV preventive strategy needs to be prioritized and for which specific populations," they write.
