New Complex Recombinant Genotype of Hepatitis B Virus Identified in Vietnam

A novel variant of hepatitis B virus was identified in Vietnam. This strain (HBV-VH24) had a novel intergenotypic recombination between genotypes A, C, and G. VH24 showed high similarity (98.3 to 98.9%) to the "aberrant strains" among Vietnamese isolates reported by Hannoun et al. (C. Hannoun et al., J. Gen. Virol. 81:2267-2272, 2000) and also had similar breakpoints of recombination. Phylogenetic analysis of the complete genome of these strains formed a separate clade. Furthermore, their pre-S/S gene-encoded seven unique conserved amino acid residues were not present in other genotypes. These findings support the designation of the new genotype I.