IL6 and influenza: ROC curve analysis revealed showed that CRP ≥ 7.57 mg/L, Serum IL-6 ≥ 9.84 pg/ml, days from onset of Flu symptoms to hospitalization ≤4.5 days, CSF-TP ≥ 194.80 mg/L and FluA increased the risk of severe influenza combined with febrile seizures.