Hepatitis D, also known as “Delta Hepatitis,” is an infection of the liver caused by the hepatitis D virus (HDV) that causes liver inflammation and damage. Hepatitis D can only occur in individuals who are already infected with the hepatitis B virus (HBV). Hepatitis D can be acute (short-term) or become a chronic (long-term) infection. Co-infection with both the hepatitis B virus and the hepatitis D virus (superinfection) is the most severe form of chronic hepatitis and can rapidly lead to the development of hepatocellular carcinoma (liver cancer; HCC) or death. Hepatitis D is transmitted by blood or body fluids through sexual contact, the shared use of contaminated needles, or infected blood transfusions.