New paradigms for treating hepatitis B in HIV/hepatitis B virus co-infected patients.

Until the advent of tenofovir, many HIV/hepatitis B virus (HBV) co-infected patients had been treated with lamivudine as the only agent active against HBV. Selection of lamivudine-resistant HBV strains occurred in many of these patients, complicating clinical prognosis and rescue therapy. These individuals might also transmit HBV-resistant strains. Moreover, a subset of these lamivudine-resistant HBV isolates may behave as vaccine escape mutants, complicating diagnostic accuracy (e.g. producing 'occult' hepatitis B) and reducing the efficacy of preventive measures (causing infection in vaccinated persons). Nowadays, periodic monitoring of HBV viral load in co-infected patients should be mandatory. It may allow the early recognition of HBV viraemic individuals who may benefit from either initiating or switching antiviral therapy. In any situation, the use of anti-HBV therapies more potent than lamivudine alone is warranted.