Background: Hepatitis B Virus (HBV) infection is a leading cause of chronic hepatitis and liver cirrhosis worldwide, and efficient protection can usually be achieved by vaccination that is based on recombinant HBsAg protein from HBV genotype A and D.
Results: Here we report the case of a fully immune-competent German patient that acquired a symptomatic acute HBV infection during adulthood despite a complete and formally successful vaccination, which had resulted in anti-HBs titers considered protective. Further phylogentic analysis identified an infection with the rare genotype F of HBV, possibly acquired in Spain, without apparent aberrations in the immunodominant 'a' determinant domain of the envelope gene. However, sequence comparisons revealed that all reported genotype F isolates display marked differences from the other genotypes in this domain which serves as an epitope for humoral immune responses.
Conclusions: The rare HBV genotype F, as detected in this immune-competent, previously vaccinated patient, has marked sequences differences in the envelope/polymerase gene. Therefore, current HBV vaccines based on genotype A and D may not result in full protective immunity towards viral strains from genotype F.