5. of childbearing potential with a negative serum pregnancy test at screening and a negative urine pregnancy test on Day 1 (Visit 2), that agree to use two non-hormonal methods of birth control from the date of screening until months after the last dose of ribavirin. They must not breast-feed at any time from the date of screening until 7 months after the last dose of ribavirin. Medically accepted methods of contraception for females in this trial are diaphragm with spermicide substance, intrauterine devices, cervical caps and condoms.