Regarded as pandemic, Hepatitis B Virus genotype A is predominantly found in North America, Northern and Western Europe as well as Central Africa. Genotype B is most common in Asia including Japan, Taiwan, Indonesia, China and Vietnam. Genotype C is predominant in East Asia and countries of the Pacific rim while genotype D, another pandemic genotype, is most common in the Mediterranean, India, the Middle East and North America. Hepatitis B Virus genotype E is mainly detected in sub-Saharan Africa, genotype F in South and Central America as well as Alaska, and genotype G in Central and North America as well as Europe. The most recent Hepatitis B Virus genotype identified, genotype H, has been found in the United States, Mexico and Central America.Recently, however, a novel genotype I has been discovered.
It is unknown whether the global distribution of Hepatitis B Virus genotypes is related to racial or ethnic differences, modes of transmission, environmental aspects or all of these factors. Further studies are required to determine the correlation of Hepatitis B Virus genotype distribution with mode of transmission or host factors including ethnicity.
Guettouche and Hnatyszyn: Chronic hepatitis B and viral genotype: the clinical significance of determining HBV genotypes in Antiviral Therapy - 2005