Pediatric Influenza-Associated Encephalopathy and Acute Necrotizing Encephalopathy — United States, 2024–25 Influenza Season
Amara Fazal, Elizabeth J. Harker, Varsha Neelam, Samantha M. Olson, Melissa A. Rolfes, Katie Reinhart, Krista Kniss, Aaron M. Frutos, Jerome Leonard, Carrie Reed, Vivien G. Dugan, Haytham Safi, Theresa M. Dulski, Adrianna Stanley-Downs, Aaliya Bhatti, Isaac Armistead, Suchitra Rao, Cristina V. Torres, Ashlin Thomas, Andy Weigel, Michael Patten, Mallory Sinner, Dawn Nims, Crystal Mattingly, Valerie Gosack, Amy Voris, Jaime Redkey, Felicia A. Scaggs Huang, Danielle DeCesaris, Carrie Tuggle, Kristina Betters, Julie Hand, Anna Krueger, Dina Z. Potter, Curi Kim, Rachel Park, Sue J. Hong, Hannah E. Edelman, Sue Kim, Justin Henderson, Melissa McMahon, Jeffrey Sanders, David A. Hunstad, Emma L. Doran, Khalil Harbi, Derek Julian, Hannah Ball, John Dreisig, Deepam Thomas, Justin Faybusovich, Yomei Shaw, Nancy Eisenberg, Richa Chaturvedi, Ashleigh Faulstich, Rachel Wester, Donna L. Gowie, Nicholas Fisher, Melissa Sutton, Sameh W. Boktor, Jonah M. Long, Patricia A. Marshall, Abby L. Berns, Lindsey McAda, Sarah Winders, Pamela Gomez Pinedo, Jade M. Murray, Ta’Kindra Westbrook, Anna Unutzer, Scott Lindquist, Thomas Haupt, Kaylyn Baum, Molly Wilson-Murphy, Carol Glaser, Kathleen Harriman, James W. Antoon, Keith Van Haren, Adrienne G. Randolph, Andrew Silverman, Annabelle de St. Maurice, Sascha Ellington, Timothy M. Uyeki, Shikha Garg, CDC Influenza-Associated Encephalopathy Collaborators, CDC Influenza-Associated Encephalopathy Collaborators, D. C. Grant, Wes Stubblefield, Sarah M. Labuda, Cassandra C Lautredou, Lori Simmons, Kalyani McCullough, Charsey Cole Porse, Pam Daily Kirley, Amanda Feldpausch, Samantha McChesney, Sayna Patel, Matthew Donahue, S. Giovanni, Layne Mounsey, Bethany Hodge, VincentP Carroll
Abstract
In January 2025, CDC received several reports of deaths among children aged <18 years with a severe form of influenza-associated encephalopathy (IAE) termed acute necrotizing encephalopathy (ANE). Because no national surveillance for IAE currently exists, CDC requested notification of U.S. pediatric IAE cases from clinicians and health departments during the 2024-25 influenza season, a high-severity season with a record number of pediatric influenza-associated deaths. Among 192 reports of suspected IAE submitted to CDC, 109 (57%) were categorized as IAE, 37 (34%) of which were subcategorized as ANE, and 72 (66%) as other IAE; 82 reports did not meet IAE criteria and were categorized as other influenza-associated neurologic disease. The median age of children with IAE was 5 years and 55% were previously healthy, 74% were admitted to an intensive care unit, and 19% died; 41% of children with ANE died. Only 16% of children with IAE who were vaccination-eligible had received the 2024-25 influenza vaccine. Health care providers should consider IAE in children with encephalopathy or altered level of consciousness and a recent or current febrile illness when influenza viruses are circulating. Annual influenza vaccination is recommended for all children aged ≥6 months to prevent influenza and associated complications, potentially including severe neurologic disease such as IAE and ANE.