Immune response to hepatitis B vaccine of subjects with isolated antibody to hepatitis B core antigen

Background/Aims: For subjects with isolated antibody to hepatitis B core antigen, vaccination can help discriminate various diagnostic possibilities. The aim of this study was to evaluate the clinical significance of isolated antibody to hepatitis B core antigen. Methodology: A total of 1403 hospital personnel were screened for hepatitis B surface antigen, antibody to hepatitis B surface antigen and antibody to hepatitis B core antigen by radioimmunoassay. Thirty subjects were confirmed to have isolated antibody to hepatitis B core antigen, and 278 subjects lacked all hepatitis B virus markers. Twenty-five of the 30 subjects (group I) and 136 of the 278 subjects (group II) were vaccinated by hepatitis B vaccine at months 0, 1, 6; followed by checking antibody to hepatitis B surface antigen in geometric mean titres at months 1, 2, and 7. Results: The geometric mean titres of antibody to hepatitis B surface antigen were higher in group I than in group II at month 1 (9.1±8.6 vs. 3.2±6.0, p<0.05), and were lower in group I than group II at month 7 (267.2±17.2 vs. 2315.3±5.1, p<0.05). Furthermore, primary response was higher in group II than group I (73.3% vs. 35.7%, p<0.05), but anamnestic response and non-response were higher in group I than group II (50% vs 26.7%, p=0.116 with a trend; 14.3% vs. 0%, p<0.01, respectively). Conclusions: For subjects with isolated antibody to hepatitis B core antigen, a strategy concerning sequential vaccination followed by checking antibody to hepatitis B surface antigen might be adopted to avoid two extra vaccine dosages and ineffective vaccination.