A Study to Assess the Safety, Pharmacokinetics, and Antiviral Activity of ABI-5366 in Healthy Participants and Participants Seropositive for HSV-2 With Recurrent Genital Herpes

Part A: Inclusion Criteria:

• Subject has a body mass index (BMI) between ≥ 18.0 and < 32.0 kg/m2

• In good health (as determined by the Investigator) based on medical history,physical examination, ECG, and clinical laboratory results.

• Female subjects must be non-pregnant and have a negative serum pregnancy test atScreening and a negative urine pregnancy test at Day -1 or Day 1 (predose)

• Agreement to comply with protocol-specified contraceptive requirements

Part B: Inclusion Criteria:

• Subject has a body mass index (BMI) between ≥ 18.0 and < 32.0 kg/m2

• Other than HSV infection, is in good health (as determined by the Investigator)based on medical history, physical examination, ECG, and clinical laboratoryresults.

• Female subjects must be non-pregnant and have a negative serum pregnancy test atScreening and a negative urine pregnancy test at Day 1 (predose)

• Agreement to comply with protocol-specified contraceptive requirements

Part A and B: Exclusion Criteria:

• Current infection of human immunodeficiency virus (HIV), hepatitis B virus (HBV),hepatitis C virus (HCV), acute hepatitis A virus (HAV), or acute hepatitis E virus (HEV).

• History of any illness that, in the opinion of the Investigator, might confound theresults of the study, pose an additional risk in administering study drug to thesubject, or a condition known to interfere with theabsorption/distribution/elimination of drugs.

• History of any significant drug-related allergic reactions such as anaphylaxis,Stevens-Johnson syndrome, urticaria, or multiple drug allergies

• History of persistent alcohol abuse or illicit drug abuse within 3 years prior toScreening

• Has participated in a clinical study involving administration of either aninvestigational or a marketed drug within 30 days or 5 half-lives before Screening,whichever is longer.