Ribavirin is a synthetic guanosine nucleoside and antiviral agent that interferes with the synthesis of viral mRNA, possessing a broad-spectrum activity against several RNA and DNA viruses (Crotty et al. 2000). It is primarily indicated for use in treating hepatitis C (HCV) and viral hemorrhagic fevers (Maag et al. 2001). Ribavirin is reported to have several mechanisms of actions that lead to inhibition of viral RNA and protein synthesis. After activation by adenosine kinase to ribavirin mono-, di-, and triphosphate metabolites, ribavirin triphosphate (RTP) is the predominant metabolite which directly inhibits viral mRNA polymerase by binding to the nucleotide binding site of the enzyme. Here, ribavirin binding to NS5B, the viral mRNA polymerase of HCV is annotated. This binding prevents the binding of the correct nucleotides, leading to a reduction in viral replication or to the production of defective virions (Te et al. 2007).
Ribavirin is currently being investigated for patients with COVID-19 (Chinese clinical trial registry no. ChiCTR2000029387) (Elfiky 2020).