Favipiravir is approved for manufacture and sale in Japan as an influenza antiviral. It selectively inhibits the RNA polymerase of the influenza virus, an enzyme required for viral replication once human host cells are infected. COVID-19 also uses this enzyme to replicate and is classified into the same type of single-stranded RNA virus as influenza; hence, it is believed that Favipiravir may be effective in treating COVID-19. Favipiravir is only used when there is an outbreak of novel or re-emerging influenza virus infections in which other influenza antiviral drugs are either not effective or insufficiently effective. Its production and distribution is at the discretion of Japan?s Health, Labor and Welfare Ministry, so has never been distributed in the market and is not available at hospitals and pharmacies in Japan or overseas.