Risk factors and prognosis in children hospitalized due to pandemic H1N1 influenza A virus infection in Ankara, Turkey*

Abstract

To describe the demographic characteristics and clinical features in children with influenza A (H1N1) virus infection and to identify risk factors for severe disease or poor prognosis. Following the first tourist-imported case in Turkey on 16 May 2009, the influenza A (H1N1) virus has spread throughout the country. Materials and methods: Children under 18 years of age who were hospitalized for at least 24 h with an influenza-like illness and who had confirmed influenza A (H1N1) virus infection were included in the study. Demographic factors, clinical signs and symptoms, laboratory results, radiographic findings, treatments, and follow-up periods were noted. Results: During the period of October to December 2009, 126 [63.5% males, median age: 3 years (range: 0.1-9 years)] children with cases of influenza A (H1N1) virus infection were hospitalized. Fever (95.2%), cough (84.1%), rhinorrhea (70%), and dyspnea (63.5%) were the most common presenting symptoms. A total of 46 patients (36.4%) had chronic underlying medical conditions, with asthma being the most common (21.4%). During hospitalization, durations of oxygen requirement and wheezing were longer in patients with chronic respiratory disease. Duration of oxygen requirement and tachypnea decreased if oseltamivir was initiated within 48 h (P = 0.006 and 0.033, respectively). No risk factor was defined for hospitalization longer than 4 days. Conclusion: In our cohort, influenza A (H1N1) virus infection did not appear to cause severe disease. Asthma was a significant risk factor for severe disease. Delayed (>48 h) initiation of antiviral therapy might have contributed to an increase in morbidity, which suggests the importance of timely administration of antiviral treatments.