RESUMEN
OBJECTIVE: To analyze the clinical features and risk factors of severe influenza virus A(IVA)pneumonia in children. METHODS: Clinical data of 617 children diagnosed with influenza virus A pneumonia who were hospitalized in Children's Hospital of Chongqing Medical University from January 2014 to March 2018 were analyzed retrospectively. Of these children there were 144 cases of severe IVA pneumonia. Logistic regression analysis was used to analyze the risk factors of severe IVA pneumonia. RESULTS: The prevalence of pneumonia associated with IVA in children was seasonal in Chongqing.The peak of IVA-associated pneumonia in 2017 was from March to May,August to October, and December to February of the following year. About 74% of patients were younger than 3 years and boy accounted for 64.1%. Among them,201(32.6%)children had underlying diseases,which were mainly malnutrition,congenital heart disease,congenital airway dysplasia and asthma. Fever and cough were the main clinical manifestations,and some were combined with gastrointestinal symptoms.Among the 617 cases,51.2% were positive for bacteria,13.9% were positive for virus other than IVA,and 12.2% were positive for Mycoplasma pneumoniae. Severe pneumonia cases progressed rapidly,and 127 children of the 144 children with severe IVA pneumonia had respiratory failure,acute respiratory distress syndrome,cardiac insufficiency and toxic encephalopathy within 3-5 days after illness onset. The multivariate analysis found that congenital heart disease(OR3.98,95%CI 2.31-6.86),nervous system disease(OR 3.33,95%CI 1.42-7.80)and malnutrition(OR 2.21,95%CI 1.29-3.79)were independent risk factors of severe pneumonia associated with IVA. CONCLUSION: Pneumonia associated with IVA in children is prevalent in winter and spring,with some summer epidemic peaks in Chongqing. Congenital heart disease,nervous system disease and malnutrition are independent risk factors for severe pneumonia associated with IVA.