Two decades of hepatitis B vaccination in mentally retarded patients: Effectiveness, antibody persistence and duration of immune memory

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 land 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. (C) 2012 Elsevier Ltd. All rights reserved.