Hepatitis A is common worldwide. Although it remains endemic in developing countries, there are falling seroprevalence rates in residents of developed countries. In young children, acute HAV infection is often asymptomatic. In contrast, older children and adults demonstrate a range of clinical manifestations from mild, anicteric infection to fulminant hepatic failure, with substantial morbidity and economic consequences. Passive immunoprophylaxis, using pooled ISG, prevents or attenuates disease in exposed individuals but does not provide long-term protection. Vaccination (active immunoprophylaxis) with predicted long-term protection against and future eradication of this disease is now possible.