In 1959, William Prusoff of Yale University discovered idoxuridine, the first effective antiviral that fights herpes by interfering with the assembly of new virus genes.

Approved in 1963 by the .S. Food and Drug Administration (FDA), it was only be used topically for herpes infections in the eye because of dangerous side effects in other parts of the body.

Since the first antiviral drug, idoxuridine approved in 1963, 90 antiviral drugs categorized into 13 functional groups have been formally approved for the treatment of the following 9 human infectious diseases.