Precore and basal core promoter hepatitis B virus (HBV) variants are present from a young age and differ across HBV genotypes.

PC variants can be present in HBV genotype A and are usually associated with C1858T that preserves the pregenome encapsidation sequence. Selection of PC and BCP variants occurred at a young age with increasing prevalence across age groups. HBeAg(+) participants with dominant PC and BCP variants progressed to the HBeAg(-) phase of chronic HBV infection significantly faster. This finding has potential clinical and therapeutic implications.