Human noroviruses are the primary cause of foodborne gastroenteritis. Potent and 
safe inhibitors are needed for the treatment/prophylaxis of norovirus 
infections. We demonstrate that Favipiravir [T-705, a drug in advanced clinical 
development for the treatment of infections with the influenza virus] inhibits 
in vitro murine norovirus replication. Time-of-drug addition studies reveal that 
T-705 exerts its activity at a time-point that coincides with onset of viral RNA 
synthesis, which is in line with the viral polymerase as the presumed target.