Hepatitis D virus (HDV) is a defective virus that always occurs as a co-infection or super-infection with hepatitis B virus (HBV). It therefore only infects people who already have HBV mono-infection. Between the two infections processes, the same modes of transmission and the same populations at risk are described.
The viral interference mechanism
Today, it is well known that the hepatitis D virus reduces certain biological activities of HBV such as HBV viral replication, new viral particles production or viremia level. Due to complex interactions between the two viruses, the exact molecular and biological mechanisms are not yet fully elucidated (1).
Aggravation of symptoms
HBV/HDV co-infection can have a serious impact on a patient's life. It is a much more severe form than hepatitis B alone. It is considered the most serious form of viral hepatitis (2). HDV can lead to severe or fulminant hepatitis. Usually HDV progresses to a chronic form of liver disease and is associated with a poor prognosis (3). In HBV/HDV co-infection, hepatic fibrosis progresses faster and cirrhotic status appears only within 5 to 10 years (4,5). Clinical manifestations such as decompensated cirrhosis or hepatocellular carcinoma (HCC) clearly impact the vital prognosis of patients who can die early (10 to 20 years earlier than during hepatitis B mono-infection) (6,7).
- Koh C et al. HBV/HDV Coinfection. A Challenge for Therapeutics. 2019. Clin Liver Dis 23 (2019) 557–572.
- Wedemeyer H. Manns MP. Epidemiology, pathogenesis and management of hepatitis D: update and challenges ahead. Nat. Rev. Gastroenterol. Hepatol. 2010; 7, 31–40.
- Negro F. Hepatitis D Virus Coinfection and Superinfection. Cold Spring Harb Perspect Med 2014;4:a021550
- Rizetto M. The Delta Agent. Hepatology 1983;3(5):729-37.
- Saracco G et al. Rapidly progressive HBsAg-positive hepatitis in Italy. Journal of Hepatology 1987;5:274-81.
- Fattovich G et al. Influence of hepatitis delta virus infection on morbidity and mortality in compensated cirrhosis type B. Gut 2000;46:420–426.
- Romeo R et al. 28-Year Study of the Course of Hepatitis Delta Infection: A Risk Factor for Cirrhosis and Hepatocellular Carcinoma. Gastroenterology 2009;136:1629–1638.