Up to 15 patients with severe H1N1 were admitted to the intensive care unit (ICU) with preexisting diseases, such as COPD. All patients were treated with Oseltamivir (Tamiflu) and 53% of the severe H1N1 patients were additionally treated with glucocorticoids (19/36). The duration of Oseltamivir treatment was based on the Pandemic Influenza A (H1N1) 2009 Clinical Guidelines (Second Edition, 2009). However, the subjects were not given immunomodulators. Treatment response did not differ significantly between the two groups and the mean duration of hospital confinement was 13.7 days (range, 0-51 days) and 3.3 days (range, 0-11 days) for the severe and moderate patients, respectively. Overall, only one severe H1N1 patient died during the course of the study. No patient dropped out and all completed the 21-week follow-up.