Photo Credit: iStock.com/Mohammed Haneefa Nizamudeen

CDC researchers recently revealed that encephalopathy was involved in 13% of pediatric flu deaths thus far during the 2024-25 influenza season.

In response to anecdotal reports of critically ill children with influenza-associated encephalopathy or encephalitis (IAE), including pediatric deaths from acute necrotizing encephalopathy (ANE), the CDC conducted an extensive investigation which revealed that IAE was implicated in 13% of pediatric influenza-associated deaths during the current influenza season. Findings from the researchers’ analysis, which encompassed data from the 2010–2011 through 2024–2025 influenza seasons and extended through February 8, 2025, were published in Morbidity and Mortality Weekly Report.

The investigation was prompted by multiple clinical observations of children presenting with severe neurologic complications amid influenza infections. According to corresponding author Amara Fazal, MD, and coauthors from the CDC’s National Center for Immunization and Respiratory Diseases, “Healthcare providers should consider IAE in children with febrile illness and clinically compatible neurologic signs or symptoms, including but not limited to seizures, altered mental status, delirium, decreased level of consciousness, lethargy, hallucinations, or personality changes lasting >24 hours.” They further noted, “Influenza-associated ANE should be considered in children with signs or symptoms of IAE, as well as rapid neurologic decline and neuroimaging demonstrating symmetric lesions affecting the bilateral thalami and other parts of the brain.”

Analysis & Findings

The analysis included a review of 1,840 pediatric influenza-associated deaths over the 15-season period, during which 9% were associated with IAE. Season-specific data showed notable variability, with the proportion of deaths linked to IAE ranging from 0% in the 2020–2021 season to 14% in the 2011–2012 season. For the 2024–2025 season, preliminary data indicated that 9 out of 68 pediatric influenza-associated deaths (13%) involved IAE, with four cases documenting ANE.

“Because no dedicated national surveillance for IAE or ANE exists, it is unknown if the numbers of cases this season vary from expected numbers,” researchers wrote.

Considering these findings, the researchers recommended that clinical evaluation of children with suspected IAE should include prompt testing for influenza and other viruses, neuroimaging, early initiation of antiviral treatment if influenza is suspected, and the provision of supportive critical care management as needed.

Strong Recommendation for Vaccination

“US influenza activity is currently elevated, and influenza viruses could continue circulating into the spring; thus, healthcare providers should provide a strong recommendation for influenza vaccination for all eligible persons aged [at least] 6 months who have not yet been vaccinated this season,” researchers wrote, “to prevent influenza illness and its associated severe and potentially fatal complications.”