All participants will receive Decavac vaccination on Day 0, and a Twinrix vaccination on Days 0, 7, and 21. Study visits will occur around Days 0, 7, and 21, and at Weeks 6, 8, 12, and 24; all visits will include medical and medication history, blood collection, and a physical exam. Medication to treat HCV or HIV will not be provided by the study.