Foundational Overview of HDV

CE / CME

Hepatitis Delta in Focus: A Foundational Overview of HDV

Pharmacists: 0.75 contact hour (0.075 CEUs)

Nurses: 0.75 Nursing contact hour

Physicians: Maximum of 0.75 AMA PRA Category 1 Credit

Released: December 09, 2022

Expiration: December 08, 2023

Nancy Reau
Nancy Reau, MD

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Populations at High Risk for HDV Infection

High-risk groups for HDV infection are predominantly people who inject drugs and commercial sex workers, followed by men who have sex with men, hepatitis C virus–infected individuals, patients with cirrhosis, HIV-infected individuals, patients with hepatocellular carcinoma, and hemodialysis recipients.6,8

Furthermore, being born in an endemic country is an additional factor that contributes to increased HDV prevalence.8

Risk also increases in those who have not been vaccinated against HBV; protection from HBV exposure eliminates risk of HDV .

Finally, mother-to-baby transmission has been documented but is still felt to be relatively uncommon.

Proportion of People With HBV Who Have HDV

Although we see people infected with HDV across the world, we have enriched regions in areas like sub-Saharan Africa and Asia.

HDV is a defective RNA virus that requires the presence of HBV, particularly HBsAg, for assembly and release to complete its life cycle.

Among HBsAg-positive individuals, there is an estimated prevalence of 4.5% to 13.0%. Up to 60 million individuals worldwide live with HDV.6,7

However, even in areas of lower endemicity, such as the United States or Western Europe, these areas still have patients with high-risk factors for HDV and immigrant populations from high endemic regions.

HDV Coinfection vs Superinfection With HBV

The natural history of HDV is different than HBV monoinfection.7

There are 2 ways people can be exposed to HDV. The first includes acquisition of HDV at the same time as HBV—or HDV coinfection—and the other route is through superinfection where the person contracts HBV first, then infection with HDV later.

If one acquires both HBV and HDV viruses at the same time, especially as an adult, there is a higher chance of spontaneous seroconversion of both viruses.

The risk of persistent disease increases in superinfection and can result in an accelerated course toward fibrosis and cirrhosis and subsequently higher risk for liver cancer and death vs HDV coinfection.

HDV vs HBV: Disease Progression

Comparing disease progression of those infected with HDV vs HBV monoinfection, patients with HDV are at higher risk for complications.

The rates of cirrhosis in HDV infection are 2-3 times higher than HBV monoinfection. The risk of liver cancer is especially high in HDV infection (3-6 times the rate of monoinfection with HDV), and we already recognize HBV as a significant risk factor for liver cancer worldwide.9

Because of the increased rates of cirrhosis and liver cancer, and because these individuals are often younger, we see high rates of liver transplantation, hepatic decompensation, and mortality.