A Longitudinal Hepatitis B Vaccine Cohort Demonstrates Long-lasting Hepatitis B Virus (HBV) Cellular Immunity Despite Loss of Antibody Against HBV Surface Antigen

Background. Long-lasting protection resulting from hepatitis vaccine, despite loss of antibody against hepatitis virus (HBV) surface antigen (anti-HBs), is undetermined. Methods. We recruited persons from a cohort vaccinated with plasma-derived hepatitis vaccine in 1981 who have been followed periodically since. We performed serological testing for anti-HBs and microRNA-155 and assessed HBV-specific T-cell responses by enzyme-linked immunospot and cytometric bead array. Study subgroups were defined 32 years after vaccination as having an anti-HBs level of either ≥ 10 mlU/mL (group 1; n= 13) or