Duration of treatment is traditionally 5 days, but treatment duration is often extended to 10 days for severely ill patients with ARDS or pneumonia or those who are immunocompromised [10]. This approach is supported by data showing slow influenza viral clearance from the lower respiratory tract in critically ill patients with influenza A(H1N1)pdm09 [16]. Of concern is the recent observation of emergence of oseltamivir resistance in 23% of 22 critically ill A(H1N1)pdm09 patients, and its association with persistent virus detection and much higher mortality [17].