Persistence of HB sAg‐specific antibodies and immune memory two to three decades after hepatitis B vaccination in adults

The duration of protection after hepatitis B vaccination is not exactly known. This phase IV study evaluated antibody persistence and immune memory 20‐30 years after adult immunization with recombinant hepatitis B vaccine ( HB sAg vaccine , Engerix‐B ) in routine clinical practice. Men and women 40‐60 years old, with documented evidence of vaccination with three or four HB sAg vaccine doses 20‐30 years earlier and without subsequent booster, were enrolled and received HB sAg vaccine as challenge dose. HB sAg‐specific antibodies (anti‐ HB s) and frequencies of HB sAg‐specific circulating memory B cells and CD 4 + T cells expressing combinations of activation markers ( CD 40L, IL 2, IFN γ, TNF α) were measured prechallenge, 7 and 30 days postchallenge. Of 101 participants in the according‐to‐protocol cohort for immunogenicity, 90.1% had anti‐ HB s concentrations ≥ 10 mIU / mL prechallenge administration; 84.2% and 100% mounted an anamnestic response 7 and 30 days postchallenge, respectively. HB sAg‐specific memory B and CD 4 + T cells expressing at least two activation markers were low prechallenge and increased markedly postchallenge. These results suggest sustained immune memory and long‐term protection 20‐30 years after a complete primary HB sAg vaccination course during adulthood, in line with current recommendations that a booster is not needed in fully vaccinated immunocompetent adults.