Vaccine
Volume 30, Issue 32 pp. 4709-4896 (6 July 2012)

Two decades of hepatitis B vaccination in mentally retarded patients: Effectiveness, antibody persistence and duration of immune memory
Original Research Article
Pages 4757-4761
Tessa Braeckman, Koen Van Herck, Wolfgang Jilg, Tanja Bauer, Pierre Van Damme

Abstract
Introduction
Institutionalized mentally retarded subjects are well-known to be at-risk for HBV infection. We studied the persistence of vaccine-induced anti-HBs antibodies and the robustness of the HBsAg-specific immune memory in this population, 18–20 years after the first vaccine dose.

Materials and methods
Non-immune residents of 4 institutions were immunized in 1984–1986. In 2004, 207 subjects were bled to determine humoral and cellular immune memory. Immune response to a booster dose was evaluated in subjects with anti-HBs level <100 IU/L.

Results
Four subjects showed anti-HBc seroconversion, without clinical implications. Pre-booster anti-HBs levels <100 IU/L were found in 45 subjects (22%); 34/39 (87%) responded with a rapid and high anti-HBs titer to the booster dose. Robust T and B cell memory was present pre- and post-booster.

Discussion and conclusion
Overall results confirm that hepatitis B vaccines are highly effective and immunogenic, and confer long-term persistence of antibodies and immune memory in an at-risk population.