When Should “I ” Consider a New Hepatitis B Virus Genotype?

Recently, Huy et al. described a new hepatitis B virus (HBV) strain isolated in Vietnam (3) and claimed it to be a “new genotype,” “HBV genotype I, ” with a complex recombination involving geno-types C, A, and G. We refute both claims. Using complete genome sequence analysis of their single isolate, VH24 (AB231908), the authors documented an over 98 % similarity with three other Vietnamese strains (2). Earlier, Hannoun et al. provided comprehensive information regarding those strains, show-ing recombination between genotype C and an unknown genotype in the pre-S/S region (2). Mean genetic divergence from genotype C of 8 % in the entire genome and evidence of recombination had prevented the authors from assigning the strains to a new genotype. The same conclusion for the strains was reached by a later study using a new methodological approach (10). By providing neither additional information nor a new analytical approach, Huy et al. (3