This is a multiple dose study of the safety and efficacy of MK-2748 to be done in 2 Parts. Part I will enroll genotype 1 (GT1) hepatitis C virus (HCV)-infected participants and Part II will enroll genotype 3 (GT3) HCV-infected participants. Both Parts may run concurrently or may be staggered.

Inclusion criteria:

• Clinical diagnosis of chronic HCV infection (GT1 or GT3) for at least 6 months and detectable HCV-RNA in peripheral blood
• Body mass index (BMI) of 18 to 37 kg/m^2
• No clinically significant abnormality on electrocardiogram (ECG)
• Stable health
• Willing to use appropriate contraception throughout the study and for 90 days after last dose of study drug

Exclusion criteria:

• Participant is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the study
• History of stroke, chronic seizures, or major neurological disorder
• History of clinically significant endocrine, gastrointestinal (excepting HCV infection), cardiovascular, hematological, hepatic, immunological, renal, respiratory, or genitourinary abnormalities or diseases
• History of neoplastic disease (exceptions of adequately treated non-melanomatous skin carcinoma or carcinoma in situ of the cervix, or other malignancies which have been successfully treated ≥10 years prior and unlikely to recur
• Positive Hepatitis B surface antigen
• Documented human immunodeficiency virus (HIV) infection
• Consumption of excessive amounts of alcohol, defined as greater than 2 glasses of alcoholic beverages (1 glass is approximately equivalent to: beer [284 mL/10 ounces],wine [125 mL/4 ounces], or distilled spirits [25 mL/1 ounce]) per day
• Consumption of excessive amounts, defined as greater than 6 servings (1 serving is approximately equivalent to 120 mg of caffeine) or coffee, tea, cola, or other caffeinated beverages per day
• Major surgery, donated or lost 1 unit of blood (approximately 500 mL) within 4 weeks prior to study enrollment
• History of significant multiple and/or severe allergies (including latex allergy), or has had an anaphylactic reaction or significant intolerability to prescription or non-prescription drugs or food
• Current regular user (including "recreational use") of any illicit drugs or history of drug (including alcohol) abuse within approximately 2 months prior to enrollment
• Evidence or history of chronic hepatitis not caused by HCV including but not limited to non-HCV viral hepatitis, non-alcoholic steatohepatitis (NASH), drug induced hepatitis, autoimmune hepatitis
• Previous treatment with other HCV NS3/4A protease inhibitors
• Previous exposure to interferon-alpha and/or ribavirin within 3 months prior to study enrollment
• Clinical or laboratory evidence of advanced or decompensated liver disease; evidence of bridging fibrosis or higher grade fibrosis (Metavir score ≥3)
• Participation in another investigational study within 4 weeks prior to enrollment