Rare Disease Database - Hepatitis B
Hepatitis D is a liver disease caused by the hepatitis delta virus (HDV). HDV is known as a “satellite virus” or an “incomplete virus” because it can only infect people who are also infected with the hepatitis B virus (HBV). Patients with an HDV infection may have an acute co-infection (an infection discovered at the same time as HBV) or a new or “superinfection” (when a patient already infected with HBV later acquires HDV). Both forms of infection can cause a chronic, long-term illness. Age of onset can occur at birth through mother to child transmission (rare), and more importantly, can occur through infection as an adult. Chronic HDV is one of the most severe forms of viral hepatitis (liver inflammation due to a viral infection) and causes more severe liver disease than having chronic HBV infection alone. Chronic HDV is also associated with a more accelerated progression of liver disease, a higher risk of liver cancer and early development of liver complications in patients who have already developed cirrhosis (end stage liver disease), liver failure, liver transplant, and death. An accurate prevalence of HDV is unknown given there is suboptimal awareness 2/8 and testing for this disease both domestically and globally. However, recent studies estimate that the prevalence of HDV ranges from 12 to 74 million individuals affected worldwide, and it likely affects 5-10% of patients with chronic HBV infection. This emphasizes the need for further research and data in order to formulate an accurate estimate of HDV prevalence and to understand which individuals are at greatest risk of HDV infection. Despite the severity of this disease and how quickly it can lead to liver damage and deterioration, there are no current recommendations from the Centers for Disease Control (CDC) or World Health Organization (WHO) to make this a reportable disease, and there are no FDA-approved therapies available for HDV treatment. One medication called bulevirtide (Hepcludex, Myr/Gilead Sciences) is approved in Europe. In addition, there are many promising therapies for HDV on the horizon.