This study is a randomized, double-blind, sponsor-open, placebo-controlled study. It will assess the safety, tolerability, pharmacokinetics and pharmacodynamics of orally administered single and multiple doses of EDP-978 in healthy adult subjects.

Inclusion Criteria:

• An informed consent document signed and dated by the subject.
• Healthy male and female subjects of any ethnic origin between the ages of 18 and 65 years, inclusive.

Exclusion Criteria:

• Clinically relevant evidence or history of illness or disease.
• Infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV), or hepatitis C virus (HCV) at screening and infection with SARS-CoV-2 at the Day -1 visit
• Pregnant or nursing females.
• History of febrile illness within 7 days prior to the first dose of study drug or subjects with evidence of active infection.
• A positive urine drug screen at screening or Day -1.
• Current tobacco smokers or use of tobacco within 3 months prior to screening.
• Any condition possibly affecting drug absorption (e.g., gastrectomy, cholecystectomy).
• History of regular alcohol consumption.
• Receipt of any vaccine, an investigational agent or biological product within 28 days or 5 times the t½, whichever one is longer, prior to first dose.