Influenza-associated encephalopathy (IAE) and the severe form termed acute necrotizing encephalopathy (ANE) occurred in 109 children in the 2024 to 2025 influenza season, according to research published in the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Following reports of deaths among children younger than 18 years with a severe form of IAE termed ANE in January 2025, Amara Fazal, M.D., from the CDC in Atlanta, and colleagues describe requested notification of U.S. pediatric IAE cases from clinicians and health departments during the 2024 to 2025 influenza season, which was a high severity season with a record number of pediatric influenza-associated deaths.
The researchers found that 192 reports of suspected IAE were submitted to the CDC, 109 (57%) of which were categorized as IAE: 34% and 66% were ANE and other IAE, respectively.
Overall, 82 reports did not meet the criteria for IAE and were classified as other influenza-associated neurologic disease. Children with IAE had a median age of 5 years; 55% were previously healthy.
Of the children with IAE, 74% and 19% were admitted to an intensive care unit and died, respectively; 41% of children with ANE died. Of children with IAE who were vaccination-eligible, only 16% had received the 2024 to 2025 vaccine.
“Health care providers should consider IAE in children with recent or current febrile illness with encephalopathy, monitor these children for clinical deterioration, and initiate appropriate supportive care,” the authors write.
More information:
Amara Fazal et al, Pediatric Influenza-Associated Encephalopathy and Acute Necrotizing Encephalopathy — United States, 2024–25 Influenza Season, MMWR. Morbidity and Mortality Weekly Report (2025). DOI: 10.15585/mmwr.mm7436a1
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