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Hepatitis D

Prevention and treatment

- Guidelines for epidemic measures
- Future considerations

Prevention
Since HDV is dependent on HBV for replication, control of HDV infection is achieved by targeting HBV infections. All measures aimed at preventing the transmission of HBV will prevent the transmission of hepatitis D. HBV vaccination is therefore recommended to avoid HBV-HDV coinfection.¹⁴

However, there is no effective measure to prevent HDV infection of chronic HBV carriers, and prevention of HBV-HDV superinfection can only be achieved through education to reduce risk behaviors.^{14, 21}

Promising research results indicate that in some woodchucks immunized with recombinant purified HDAg-S complete protection is possible.

Hepatitis B Ig and HB vaccine do not protect HBV carriers from infection by HDV.

Treatment
Currently there is no effective antiviral therapy available for treatment of acute or chronic type D hepatitis.²¹

For infected patients, massive doses of a-interferon (9 million units three times a week for 12 months or 5 million units daily for up to 12 months) have yielded remissions, but most patients remained positive for HDV RNA despite the improved disease conditions.²¹

The effect of interferon is considered to be most likely an indirect one, possibly via an effect on the helper hepadnavirus and/or on the immune response to the infections.²⁵

Acyclovir, ribavirin, lamivudine and synthetic analogues of thymosin have proved ineffective.¹⁰

Immunosuppressive agents do not have any effect on hepatitis D.^{14, 21}

Liver transplantation has been helpful for treating fulminant acute and end-stage chronic hepatitis.^{11, 21} In one study, the 5-year survival rate of transplant patients for terminal delta cirrhosis was 88% with reappearance of HBsAg only in 9% under long-term anti-HBs prophylaxis.¹⁰

Guidelines for epidemic measures 1.) When two or more cases occur in association with some common exposure, a search for additional cases should be conducted.
2.) Introduction of strict aseptic techniques. If a plasma derivative like antihaemophilic factor, fibrinogen, pooled plasma or thrombin is implicated, the lot should be withdrawn from use. 3.) Tracing of all recipients of the same lot in search for additional cases.

Future considerations
Whether or not immunization with HDAg can confer protection against superinfection or slow the progression of liver disease in the over 350 million HBV carriers who are at risk of contracting type D hepatitis, needs to be determined.²¹