Hepatitis D epidemiology and demographics

Epidemiology
HDV is rare in most developed countries, and is mostly associated with intravenous drug abuse. However HDV is much more common in Mediterranean countries, sub-Saharan Africa, the Middle East, and countries in the northern part of South America. In all, about 20 million people may be infected with HDV.

Hepatitis D infections occur globally, but the prevalence varies widely among countries. An estimated 10 million people worldwide have dual infections with hepatitis D and hepatitis B viruses. Hepatitis D infection occurs epidemically or endemically in populations at risk of hepatitis B virus infection, such as populations in countries where hepatitis B is endemic (e.g., Russia, Romania, southern Italy, Africa and South America);  in hemophiliacs, intravenous drug addicts and others who come in frequent contact with blood; in institutions for the developmentally disabled; and, to a much lesser extent, in men having sex with men.

Viral hepatitis D is of concern to drug treatment programs because of its association with hepatitis B, which affects up to 80 percent of injection drug users in some areas. The prevalence of HDV is estimated to be 20 to 53 percent among drug users who are HBsAg positive. HDV is clinically important because persons co-infected with hepatitis B and HDV are at increased risk of developing more severe liver disease. Hepatitis B vaccination will effectively prevent delta hepatitis. It is mandatory that persons infected with HBV who are HBsAg positive alter their risk-associated behavior to avoid infecting persons not previously exposed to hepatitis B with hepatitis B alone or with both hepatitis B and D if co-infection is present.