Synergistic in vitro interactions between alpha interferon and ribavirin against bovine viral diarrhea virus and yellow fever virus as surrogate models of hepatitis C virus replication.

Monotherapy of hepatitis C virus infection with either alpha interferon or ribavirin alone is rather ineffective, while the use of the two antivirals together is much more efficacious. In vitro drug-drug combination analysis utilizing related members of the family Flaviviridae, bovine viral diarrhea virus and yellow fever virus, revealed significant direct synergistic interactions between these drugs' antiviral activities that might explain this clinical observation.