The clinical courses and outcomes of patients in our study with the pandemic H1N1 2009 influenza virus infection were much better than those of previously reported cases (3, 4) . We attribute this to the patient population of our study. All of our patients were healthy young soldiers without any risk factors for complications. Furthermore, according to military rule, any problems concerning health must be notified to the medical department immediately, and thus, our patients may have been detected at an earlier stage of the disease course than would be found for the general population. In comparison with a previous report (3) that showed a high mortality rate in patients with the pandemic H1N1 2009 influenza virus infection, the interval between symptom onset and the emergency department visit (mean 1.7 days in 15 among 18 patients) and symptom onset and the start of antiviral agent therapy (mean 3.9 days) were shorter. In addition, detection and treatment were made more promptly. Therefore, we conclude that an early diagnosis and early antiviral management can improve the clinical course and outcome of the pandemic H1N1 2009 influenza virus infection. However, to understand the detailed relationship between symptom onset to admission or antiviral management and clinical courses or outcomes, further study, including a comparative analysis with a large case series, is warranted.