Long-term monitoring drug resistance by ultra-deep pyrosequencing in a chronic hepatitis B virus (HBV)-infected patient exposed to several unsuccessful therapy schemes

► This is 11-year longitudinal analysis of HBV genomics by ultra-deep pyrosequencing. ► Persistent HBV viremia on tenofovir without HBV mutations that reduce the drug-sensitivity. ► The UDPS allowed for low-prevalence HBV variants detection. ► HBV-S gene mutants associated with immune evasion were detected. ► First study describing the dynamics of HBV drug-resistance mutations by UDPS.