Virulence may determine the necessary duration and dosage of oseltamivir treatment for highly pathogenic A/Vietnam/1203/04 influenza virus in mice

Abstract

Background. Control of highly pathogenic avian H5N1 influenza viruses is a major public-health concern. Antiviral drugs could be the only option early in the pandemic. Methods. BALB/c mice were given oseltamivir (0.1, 1, or 10 mg/kg/day) twice daily by oral gavage; the first dose was given 4 h before inoculation with H5N1 A/Vietnam/1203/04 (VN 1203/04) virus. Five- and 8-day regimens were evaluated. Results. Oseltamivir produced a dose-dependent antiviral effect against VN1203/04 in vivo (P < .05). Overall, the efficacy of the 5- and 8-day regimens differed significantly (death hazard ratio, 2.658; P