Does the spread of hepatitis B virus genotype A increase the risk of intrafamilial transmission in Japan?
Recently, the prevalence of genotype A in patients with acute hepatitis B virus (HBV) infection has markedly increased in Japan. We encountered a 1-year-old infant who was infected with HBV genotype A and became an HBV carrier. His grandfather was identified as an HBV carrier; however, the grandfather was not aware of chronic HBV infection. This was a case of intrafamilial transmission. In addition, the child's father developed acute hepatitis B within 1 month of the infant's diagnosis. Molecular analysis revealed that the HBV isolates from the grandfather, the infant, and the father had identical sequences that belonged to genotypes A2/Ae. Compared with other HBV genotypes, genotype A has a significant association with chronic outcome. Therefore, prolonging hepatitis can increase the risk of transmitting the virus without realizing. The at-risk strategy of hepatitis B vaccination, which has been adopted in Japan, cannot prevent such intrafamilial transmission. Universal vaccination in childhood is only one way to prevent young children from unexpected HBV infection.
Komatsu
Haruki
H
Department of Pediatrics, Eastern Yokohama Hospital, 3-6-1 Simosueyoshi, Tsurumi-ku, Yokohama, Kanagawa, Japan. haruki-komatsu@chive.ocn.ne.jp
Sugawara
Hidenori
H
Inui
Ayano
A
Nagamine
Kenjiro
K
Hiejima
Eitaro
E
Sogo
Tsuyoshi
T
Fujisawa
Tomoo
T
D000328:Adult; D002353:Carrier State / Q000635:transmission / Q000821:virology; D018562:Disease Transmission, Infectious; D005190:Family; D005260:Female; D005838:Genotype; D006509:Hepatitis B / Q000635:transmission* / Q000821:virology; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics*; D006801:Humans; D007223:Infant; D007564:Japan; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA
D006514:Hepatitis B Surface Antigens