Transmission of genotype A (A2) hepatitis B virus from patients who developed acute hepatitis B to their sexual partners, via interspousal or homosexual infection

Abstract

We report herewith the transmission of genotype A (A2) hepatitis B virus (HBV) from patients who developed acute hepatitis B to their sexual partners, through interspousal or homosexual infection. The four HBV isolates obtained from two pairs of the index patient and his partner with a secondary infection shared 99.9-100% identities over the entire genome, although each pair of the patients lived in distinct areas, and segregated into a phylogenetic cluster consisting of indigenous HBV/A2 strains isolated in different prefectures in Japan. These results indicate a wide distribution of HBV/A (A2) in Japan that can be transmitted not only from persistently infected patients but also from those with acute HBV infection, and the need for HB vaccination of at-susceptible people to prevent increase in HBV infection in Japan.