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Hepatitis D - Epidemiology
Medical expert of the article
Last reviewed: 04.07.2025
The main source of the HDV infection pathogen is individuals with chronic forms of HBV infection infected with HDV.
The mechanism of transmission of HDV infection is very similar to the transmission of HBV infection. Delta virus is transmitted parenterally, mainly with blood. The risk of contracting delta infection is especially high for regular recipients of donor blood or its products (i.e., hemophiliacs); for individuals undergoing frequent parenteral interventions, as well as for drug addicts who inject drugs intravenously; for individuals who have contact with blood. Infection often occurs in surgical departments and hemodialysis centers.
Transplacental transmission of HDV from a pregnant woman to her fetus is possible, mainly in HBe-positive mothers infected with HDV. Perinatal transmission is also quite rare, but the development of co-HBV-HDV infection in newborns is possible.
HDV infection has been found to spread within families, especially among children, in most cases in the absence of registered parenteral interventions, suggesting a natural route of transmission of delta infection. The high frequency of HDV infection among individuals leading a promiscuous sex life (especially among homosexual men) suggests that sexual transmission is also possible.
Patients with acute or chronic forms of viral hepatitis B are susceptible to delta infection, especially HBs-antigen carriers. HDV infection leaves a strong immunity.
For HDV replication, structural components of HBV (HBsAg) are necessary, so delta infection never occurs independently and develops only against the background of HBV infection. About 5% of HBs antigen carriers in the world (approximately 18 million people) are infected with HDV.
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