Emergence of Oseltamivir-Resistant Pandemic H1N1 Virus during Prophylaxis

Abstract
Neuraminidase inhibitors (oseltamivir and zanamivir) are recommended for treatment of severe illness caused by the 2009 pandemic influenza A (H1N1) virus, and their use has also been advocated for postexposure prophylaxis in high-risk persons.1 We report the emergence of an oseltamivir-resistant virus in a familial cluster of infections with the 2009 H1N1 virus.