Hepatitis D By Sonal Kumar, MD, MPH, Weill Cornell Medical College Reviewed / Revised Aug 2022 | Modified Sep 2022 View Patient Education Symptoms and Signs Diagnosis Treatment Prevention Key Points Hepatitis D is caused by a defective RNA virus (delta agent) that can replicate only in the presence of hepatitis B virus. It occurs uncommonly as a coinfection with acute hepatitis B or as a superinfection in chronic hepatitis B.