- Known history of or positive test result for antibodies to hepatitis C, or current hepatitis B infection (defined as positive for hepatitis B surface antigen [HBsAg] and/or positive for hepatitis B core antibody [HBcAb]) at Screening. Participants with immunity to hepatitis B from either active vaccination (defined as negative HBsAg, positive hepatitis B surface antibody [HBsAb], and negative HBcAb) or from previous natural infection (defined as negative HBsAg, positive HBsAb immunoglobulin G, and positive HBcAb) are eligible to participate in the study (definitions are based on the Centers for Disease Control and Prevention's interpretation of the hepatitis B serology panel [CDC 2007]).