Significance of Response to Hepatitis B Recombinant Vaccine in Subjects with Isolated Antibody to Hepatitis B Core Antigen

BACKGROUND It is important to differentiate whether isolated anti-HBc is due to false positive results or the prior exposure to hepatitis B virus, because individuals with false-positive anti-HBc can benefit from vaccination and their blood can be safely transfused. To distinguish between these two conditions, we evaluated the serologic response to hepatitis B vaccine. METHODS Ninety subjects with isolated anti-HBc (cases) and 100 subjects with totally negative hepatitis B serologic markers (controls) were recruited to receive three doses of hepatitis-B (HB) vaccine. Thirty days after the first dose of the vaccine, anti-HBs titers were checked and individuals with anti-HBs titer >50 mIU/mL did not receive additional doses of the vaccine. However, others completed the vaccination course, and another blood sample was collected 30 days after the third dose to measure anti-HBs level.