Study of hepatitis B (HB) vaccine non-responsiveness among health care workers from an endemic area (Taiwan)

Objective: To evaluate the etiology of non-responsiveness to hepatitis B (HB) vaccination in adults from an endemic area. Methods: A total of 250 subjects who were HBsAg negative and anti-HBs<l0mIU/ml received three-dose HB-vaccine series. Anti-HBs 'negative' was defined as a level<1.5 mIU/ml. 'Weakly' positive was defined as 1.5-10 mIU/ml at prevaccination testing. Anti-HBs response was defined as a level > 10 mIU/ml at post-vaccination testing. Among non-responders who were anti-HBc positive, serum anti-HBe and hepatitis B virus (HBV) DNA were tested. Results: Three variables were associated with non-responsiveness by univariate analysis: anti-HBc positive, male gender, and age >40 years. Multivariate analysis additionally showed that anti-HBs negative was associated with non-responsiveness. Among 23 non-responders in anti-HBc positive subjects, post-vaccination serum was available in 16 subjects. HBV-DNA in all subjects was under detectable level by PCR assay. Anti-HBe positive were found in 13 of 16 subjects and were assumed to be occult HBV infection. Conclusion: Male gender, age >40 years and anti-HBc positive are associated with non-responsiveness to HB vaccination. Most of nonresponders among anti-HBc positive subjects were assumed to be occult HBV infection. Subjects with weakly positive anti-HBs were associated with responsiveness which may be the effect of immune memory.