Rare Flu Complication On The Rise In Children As Vaccination Rates Dwindle

Getting the flu sucks. But for the vast majority of people, they make it through just fine with no lingering complications. However, regardless of age or health, influenza can present devastating complications and can even prove deadly. One such complication is acute necrotizing encephalopathy (ANE) — a neurological condition characterized by rapid brain inflammation and tissue death (necrosis) following a viral infection. ANE is rare, and primarily affects children. But a recent study examined cases across the country and found that ANE appears to be on the rise, confirming some doctors’ observations.

The paper, published this week on the JAMA Network, came about as doctors began to individually observe an uptick in cases of ANE during the 2023-2024 and 2024-2025 flu seasons (October through March). Researchers looked at the cases of 41 children across 23 hospitals in the US who had flu-associated ANE. The complication carried a 27% mortality rate despite treatment. Most patients — more than three-quarters — had no significant medical history while the remaining 12% were medically fragile or complex. Patients who died generally did so within three days from symptom onset. Among survivors, 63% were found to have a moderate to severe disability at 90-day follow-up appointment.

Crucially, only 16% had received seasonal influenza vaccination, reflecting an overall decrease in flu shot uptake per data from the Centers of Disease Control and Prevention (CDC). During the 2023-2024 flu season, only about 55% of children under the age of 17 received their recommended dose. Of the 266 children who died of flu this past season, 90% were unvaccinated against the virus.

Patients who presented with ANE almost all had fevers and 68% also experienced seizures. A full 95% of patients who experienced ANE contracted it after an influenza A infection. Among the 32 patients who had been genetically tested, a little less than half were found to have genetic risk alleles that might have pre-dispositioned them toward a risk of ANE, but this is not a risk that could be casually observed outside of genetic testing.

“The findings emphasize the need for prevention, early recognition, intensive treatment, and standardized management protocols,” the paper concludes. “Critical knowledge gaps remain, particularly regarding optimal treatment protocols, timing of interventions … and long-term outcomes beyond the 90-day follow-up period reported in this study.”

Unfortunately, symptoms of ANE can develop quickly and often coincide with general viral infections including congestion, cough, fever, vomiting and diarrhea. As ANE progresses, symptoms can become more severe, including fainting, seizures, trouble breathing, and poor movement and coordination.

The American Academy of Pediatrics recommends seasonal flu immunization for all children over 6 months old unless they have a particular medical reason they cannot receive the vaccine. At the moment, it is the best protection against both flu and flu related ANE.