HBV Drug-Resistant Mutations and Vaccine Escape

Hepatitis B virus (HBV) polymerase and envelope genes overlap, such that polymerase mutations associated with drug resistance may alter antigenic sites in hepatitis B surface antigen (HBsAg). A triple mutational pattern that confers lamivudine (3TC) resistance (rtV173L + rtL180M + rtM204V) reduces binding of antibody to HBsAg; if transmitted, this mutant virus could escape vaccine-induced protection. How frequently does selection of vaccine-escape mutants occur in patients on anti-HBV therapy?

To address this question, investigators performed HBV sequencing in 19 monoinfected and 52 HIV-coinfected patients who were treated for at least 12 months with anti-HBV nucleosides (3TC or emtricitabine), nucleotides (tenofovir or adefovir), or both. T…