Hepatitis Delta Virus Epidemiology in the Industrialized World

Within the hepatitis virus landscape, one incomplete virus, the hepatitis delta virus (HDV), appears to differ from hepatitis B and C viruses in the context as it still may not infrequently lead to complications of chronic liver disease and continues to be associated with significant liver-related mortality even when patients have received available treatment for it. Breakthrough therapies are so far lacking for HDV-infected patients and treatment has not changed since the discovery of HDV in 1977 and consists mainly of interferons. While there was little interest on the global epidemiology of HDV until recently, this has changed in the past 2 years and we are currently observing a stream of papers on the global epidemiology of HDV and commentaries about why prevalence estimates appear to differ so dramatically. This may be related to the fact that reliable data are not available for most of the countries. However, in the industrialized world, data on the epidemiology of HDV are expected to be of better overall quality. Hence, this review was undertaken to provide a detailed overview on the epidemiology of HDV infection in industrialized countries using data from representative larger countries. In industrialized countries, with maybe the exception of China, HDV infection is a disease of high-risk groups. Migrant groups and people who inject drugs are the most encountered high-risk groups. This review summarizes the dynamics of their contribution to the HDV epidemiology in industrialized countries of the west and the east.