Topic overview

Start with the big picture

A useful starting point is to compare hepatitis viruses by transmission, chronicity, and vaccine availability. HAV and HEV are generally associated with fecal–oral spread, while HBV, HCV, and HDV are linked to blood or sexual exposure; HDV also requires HBV. HAV does not become chronic, whereas chronic infection is important in HBV and HCV and can occur with HEV in immunosuppressed people. Prevention and management differ: vaccines protect against HAV and HBV, and HBV vaccination also prevents HDV. HBV and HCV care involves antiviral treatment and follow-up, with drug interactions and reactivation risk relevant to treatment decisions. Serology markers provide clues to active HBV infection, immunity, acute infection, and infectivity. The broader topic also introduces drug-induced hepatitis and supportive care.