Which non-HIV antiviral medication is effective across the broadest spectrum of viruses?

Ribavirin is recognized for its broad spectrum of antiviral activity, making it effective against a variety of RNA and DNA viruses beyond just HIV. It is primarily used in the treatment of viral infections such as hepatitis C and certain viral hemorrhagic fevers, and it has demonstrated activity against a range of other viruses, including respiratory syncytial virus (RSV) and some flaviviruses. This multifaceted efficacy is what distinguishes ribavirin as a significant therapeutic agent in the realm of antiviral medications.

In contrast, acyclovir is primarily effective against herpes viruses, impacting conditions like herpes simplex and varicella-zoster. Oseltamivir and zanamivir are both antiviral medications specifically targeting influenza viruses by inhibiting their neuraminidase enzyme, thus limiting their replication. This narrower focus on specific viral families makes them less versatile than ribavirin when considering the spectrum of viruses they can combat.