To determine the frequency of neurologic complications associated with influenza in hospitalized children.
We performed a cross-sectional study of children 2 months through 17 years of age) with influenza discharged from 49 children’s hospitals in the Pediatric Health Information System during the influenza seasons of 2015-2020. Neurologic complications were defined as encephalopathy, encephalitis, aseptic meningitis, febrile seizure, non-febrile seizure, brain abscess and bacterial meningitis, Reye syndrome, and cerebral infarction. We assessed length of stay (LOS), intensive care unit (ICU) admission, ICU LOS, 30-day hospital readmissions, deaths, and hospital costs associated with these events. Patient-level risk factors associated with neurologic complications were identified using multivariable logistic regression.
Of 29,676 children hospitalized with influenza, 2246 (7.6%) had a concurrent diagnosis of a neurologic complication; the most frequent were febrile seizures (5.0%), encephalopathy (1.7%), and non-febrile seizures (1.2%). Hospital LOS, ICU admission, ICU LOS, deaths, and hospital costs were higher in children with neurologic complications compared with those without complications. Risk factors associated with neurologic complications included male sex (adjusted odds ratio (aOR) 1.1, 95% CI 1.02-1.21). Asian race/ethnicity (aOR 1.7, 95% CI 1.4-2.1) (compared with non-Hispanic whites), and the presence of a chronic neurologic condition (aOR 3.7, 95% CI 3.1-4.2).
Neurologic complications are common in children hospitalized with influenza, especially among those with chronic neurologic conditions, and are associated with worse outcomes compared with children without neurologic complications. These findings emphasize the strategic importance of influenza immunization and treatment, especially in high-risk populations.

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