Reduced sensitivity of influenza A (H5N1) to oseltamivir

We tested the neuraminidase drug sensitivity of clade 1 and clade 2 influenza A (H5N1). All viruses demonstrated similar sensitivity to zanamivir, but compared with the 2004 clade 1 viruses, the Cambodian 2005 viruses were 6-fold less sensitive and the Indonesian clade 2 viruses were up to 30-fold less sensitive to oseltamivir.