Table 3.

Characteristics of Hepatitis B Virus Genotypes.

Genotypes	Subtypes	Origin/Geographic Distribution	Clinical Notes	Predominant Route of Transmission	Mutations/Recombinations	Response to Antiviral Therapy
A	A1	Africa	More likely to lose HBsAg than C and D A1 is associated with aggressive liver disease	Parenteral or sexual	Higher frequency of BCP mutations than B and D	Responds better to interferon therapy than C and D
	A2	Europe/North America
	A3	Africa/Haiti
B	B1	Japan	Lower HBsAg than A and D More likely to lose HBsAg than C and D B1 is associated with fulminant hepatitis	Perinatal	93% of strains have recombination	Responds better to interferon therapy than C and D
	B2	China
	B3	Indonesia, China, Philippines
	B4	Vietnam, Cambodia, France
	B5	Eskimos, Inuits
C	C1	Thailand, Myanmar, Vietnam	High replication capacity can result in more severe disease Slower progression to HBeAg seroconversion Lower HBsAg levels than A and D	Perinatal	Higher frequency of BCP mutations than B and D
	C2	Japan, China, Korea
	C3	New Caledonia, Polynesia
	C4	Australian aborigines
	C5‐C12	Philippines, Indonesia
	C13‐C16	Indonesia
D	D1	Middle East, Central Asia	Early HBeAg seroconversion D3 often associated with OBI	Horizontal	High prevalence of precore mutations
	D2	Europe, Lebanon
	D3	Universal
	D4	Pacific Islands, Papua New Guinea, Arctic Denes, India
	D5	India
	D6	Tunisia, Nigeria
E	None	Africa—Western and Central		Horizontal
F	F1	Argentina, Costa Rica, El Salvador, Alaska		Horizontal
	F2	Nicaragua, Venezuela, Brazil
	F3	Venezuela, Colombia
	F4	Argentina
G	None	France, Germany, United States		Horizontal: sexual transmission in men who have sex with men	Two stop codons prevent HBeAg expression; requires another genotype, usually A, to establish CHB
H	None	Mexico, Japan, Nicaragua, United States	Often associated with OBI
I	I1	Vietnam, Laos, China		Perinatal	Recombinant of A, C, G
	I2	Vietnam, Laos, India
J (putative)		Japan/Borneo

Data are compiled from Honer et al. (2017),1 Kramvis (2014),8 and Sunbul (2014).9