Facts and Figures
In the United States, hepatitis D is estimated to affect approximately 5% of hepatitis B patients, correlating to less than 200,000 coinfections, and classifying it as a rare disease by the NIH. Hepatitis B and D coinfection is more common in certain parts of the world including Mongolia, Romania, Russia, Pakistan, the Middle East, Georgia, Turkey, Pakistan, West and Central Africa, and the Amazonian river basin. Globally 15-20 million people are thought to be affected, although a recent meta-analysis suggested there may be as many as 62–72 million coinfections.
The risk of progression to cirrhosis, including the risk of liver cancer, liver transplant, and death is in the 70% range, when patients have chronic hepatitis delta co-infection along with chronic hepatitis B.
There are at least 8 different types of hepatitis D called “genotypes,” which are associated with distinct disease progression. In general, a more severe disease occurs in genotype 1 and 3, and a milder disease in genotype 2. Although a single genotype tends to dominate in an infected person, multiple genotypes can occur in those at high risk for repeated exposure to the virus.
Prevalence and Genotypes of Hepatitis D Around the World
Source: Eiger Biopharmaceuticals
- Genotype 1– most common and found worldwide, especially Europe, the Middle East, North America and North Africa
- Genotype 2 – found in Japan, Taiwan and Russia
- Genotype 3 – found exclusively in Amazonian region of South America
- Genotype 4 – found in Japan and Taiwan
- Genotypes 5 - 8 – identified primarily in Africa
While testing exists to determine the hepatitis D genotype, it is not widely available or recommended due to the lack of reliability of the current tests.