In the 217 hospitalized children, the mean age was 6.2 ± 3.7 years, and the male-to-female ratio was 1.6:1 (132/85). Almost all the patients had a high fever (97.2%) and cough (92.6%) suggestive of severe infection such as pneumonia at the time of admission. Most of the patients were previously healthy although some had underlying diseases and only 17 patients had underlying disorders (7.8%), including 11 chronic pulmonary diseases (10 patients with bronchial asthma and one with past history of brochopulmonary dysplasia), 4 neuromuscular disorders (two with epilepsy and two with cerebral palsy), one with chronic liver disease, and one with nephrotic syndrome. The outcomes for these patients were uneventful, except for two asthmatic patients who developed a mild pneumonia. All inpatients received oseltamivir of the recommended doses for body weight and a broad-spectrum antibiotic (ampicillin/sulbactam). Two hundred and five patients (94.5%) received oseltamivir within 48 h of fever onset. The mean duration of fever before admission (including the day of admission) was 2.0 ± 0.8 d and 167 patients (77%) defervesced on the next day. Only seven patients had fever that persisted > 48 h after oseltamivir treatment. During hospitalization, five patients showed progressive pneumonia despite early antiviral therapy.