Study Flags RSV Deaths in Kids Not Eligible for Protection

Children and adolescents ineligible for respiratory syncytial virus (RSV) immunization accounted for a substantial proportion of the RSV-associated intensive care unit (ICU) admissions and deaths in recent years, a U.S. cohort study suggested.

From 2017 to 2023, children 2 years and older accounted for 46.9% of the pediatric RSV-related ICU cases and 65.9% of the RSV-related deaths, according to a multicenter analysis from researchers led by Taylor Olson, MD, of Children’s National Hospital in Washington, D.C.

Children who died were significantly older than those who survived (median 9.1 vs 6.5 years), and the vast majority of deaths (93.8%) among those 2 and up had at least one complex chronic condition, findings in JAMA Network Open showed.

“Our study demonstrated that older children and adolescents with medical complexity account for a disproportionate share of RSV-associated critical illness,” Olson told MedPage Today. “These children represent an important population for development of prevention strategies.”

Children with one or more complex chronic conditions were nearly 13 times more likely to die (OR 12.76, 95% CI 8.79-18.53) and kids with three or more were 22 times more likely to die (OR 22.56, 95% CI 15.44-32.97) compared to those without a complex medical condition.

RSV accounts for about 10% of all U.S. infant hospitalizations and drives almost 80,000 hospital admissions every year, but immunizations against the annual scourge — which first came to the U.S. market in 2023 — are not recommended for children 2 years and up.

“For older children, including those with medical complexity, current practice focuses on general infection-control measures and medical optimization of underlying conditions,” Olson explained.

On multivariable analysis, the complex conditions most strongly linked with mortality included malignant neoplasms (adjusted odds ratio [aOR] 4.27, 95% CI 3.16-5.77), neurologic or neuromuscular conditions (aOR 2.66, 95% CI 2.08-3.39), respiratory conditions (aOR 2.36, 95% CI 1.83-3.03), and receipt of transplant (aOR 2.18, 95% CI 1.47-3.23). Congenital or genetic conditions, metabolic conditions, cardiovascular disease, and technology dependence were also associated with RSV-related mortality.

The American Academy of Pediatrics recommends infants receive protection before their first RSV season either via maternal vaccine or with one of the approved monoclonal antibodies, nirsevimab (Beyfortus) or clesrovimab (Enflonsia). Nirsevimab is also approved for high-risk kids under 2 years of age entering their second RSV season.

Federal recommendations had largely mirrored those until this year, when Health Secretary Robert F. Kennedy Jr. — a prominent anti-vaccine activist before becoming the nation’s top health official — and President Trump downgraded the RSV immunization guidance to just high-risk infants. A federal judge has so far blocked some of the major changes to U.S. vaccine policy.

Olson said that more research is needed to determine whether expanding prevention strategies in older kids would improve outcomes.

Using the Oracle Electronic Health Record Real-World Data database, a repository covering records from more than 100 U.S. health systems, the researchers identified 13,732 pediatric ICU admissions from January 2017 to June 2023 where RSV was involved, including 735 deaths.

Of those, 6,430 involved children 2 years and older. Median patient age was 6.6 years, 54% were boys, more than half (57.2%) had a complex chronic condition, and roughly a fourth had three or more. Among the 484 deaths in this group, 30.8% occurred in 2- to 4-year-olds, 39.5% in those ages 5 to 12, and 29.8% among those 13 to 17 years.

While children with complex chronic conditions accounted for most deaths, Olson and colleagues emphasized that severe RSV and ICU admissions weren’t entirely dependent on medical complexity.

For example, 53.8% of children 2 to 5 years in the study had no identifiable complex chronic condition. That percentage underscores “that previously healthy children remain at risk for severe RSV disease beyond infancy, even though their risk of death is comparatively low,” the authors cautioned.

Study limitations included variability in diagnostic and procedural coding, which prevented the researchers from determining the degree to which RSV contributed to critical illness or death. They also couldn’t account for all confounders such as viral or bacterial coinfections.

Moreover, confining the analysis to ICU admissions limited generalizability to children with less severe RSV. “Consequently, our findings should not be interpreted as demonstrating that [complex chronic conditions] are associated with the risk of developing severe RSV disease or requiring ICU admission at the population level,” Olson and colleagues warned.