Which Hepatitis subtype requires the presence of Hepatitis B virus for replication?

• A. Hepatitis A
• B. Hepatitis C
• C. Hepatitis D
• D. Hepatitis E

Answer: (C)

Hepatitis D requires Hepatitis B for replication. It is a defective RNA virus that cannot form infectious particles on its own and depends on the Hepatitis B surface antigen to envelope and assemble HDV virions. Because of this dependency, HDV can only propagate in people who have an active HBV infection or who acquire HBV first. Vaccination against Hepatitis B prevents HDV infection because without HBV, there is no envelope for HDV to use. In contrast, Hepatitis A and E are non-enveloped enteric viruses, and Hepatitis C is an enveloped virus that replicates independently of HBV, so none of them require HBV for their replication.