According to preliminary statistics, nine out of 68 (13%) recorded pediatric flu-related deaths during the 2024–2025 season (until February 8, 2025) had influenza-associated encephalopathy or encephalitis (IAE), including four with the most severe form, acute necrotizing encephalopathy (ANE).
166 (9%) of the 1,850 pediatric flu-related deaths the CDC received during the 2010–11 through 2023–24 flu seasons included IAE. It is unknown if the IAE and ANE cases reported this season fall within expected ranges because there is currently no national IAE surveillance.
„Children, especially those younger than age 5 with certain underlying medical conditions, can experience severe or fatal complications associated with influenza virus infection. IAE, including ANE, are rare, serious complications of flu that can lead to the development of permanent neurologic impairment and death. CDC investigators reviewed data from the U.S. Influenza-Associated Pediatric Mortality Surveillance System to assess trends in encephalopathy or encephalitis complications among flu-related deaths in children reported to the CDC during the 2010–11 through 2024–25 seasons. CDC also contacted state health departments to investigate whether any reported pediatric flu-related deaths with IAE during the 2024-25 flu season had a diagnosis of ANE,” CDC recently announced.
Taking IAE Into Consideration
When evaluating children with recent or ongoing acute respiratory illness and clinically compatible neurologic signs or symptoms, such as seizures, altered mental status, delirium, decreased level of consciousness, lethargy, hallucinations, or personality changes that last longer than 24 hours, healthcare providers should consider IAE. Testing for influenza and other viruses, neuroimaging, early antiviral treatment initiation if influenza is suspected (i.e., providers should not wait for laboratory confirmation of influenza before initiating antiviral treatment), and supportive critical care management, as required for patients with IAE, are all important components of comprehensive assessment and management.
There is currently a high level of flu activity in the US, and influenza viruses may persist throughout the spring. For all eligible individuals aged 6 months and older who have not had a vaccination this season, healthcare practitioners should strongly advise getting vaccinated against the flu and its linked, possibly deadly consequences.
„CDC flu experts investigate neurologic complications of influenza to better understand the severity of the disease and recommend prompt testing and treatment,” the CDC experts concluded.
