Anti-hepatitis B core antibody is not required for prevaccination screening in healthcare workers

Vaccination against hepatitis B virus (HBV) is recommended for health care workers (HCWs), but it is not clear whether HBV vaccination is required for HCWs who have isolated antibody to hepatitis B core antigen (anti-HBc), or whether prevaccination screening for anti-HBc is needed in HCWs. Among 1812 HCWs, subjects with isolated anti-HBc and those with no HBV markers (control) were screened. The anamnestic response (antibody to hepatitis B surface antigen over 50mIU/mL after the first vaccine injection) was compared prospectively between the two groups. The prevalence of isolated anti-HBc was 2.3%. Their anamnestic response was lower than that of controls (27.5% vs. 46.9%, P=0.020). The subjects who had isolated anti-HBc were older and predominantly male, compared with the controls. Multivariate analysis revealed that age (oddsratio[OR], 0.67;confidence interval[CI], 0.51-0.90)andprior vaccination (OR, 3.36; CI, 2.04-5.54) were independent predictors of the anamnestic response, regardless of the anti-HBc status. Serum HBV DNA was not detected in any subject. Anti-HBs seroconversion was achieved in most of the anti-HBc-positive subjects after full vaccination, and the rate was comparable with controls (89.5% vs. 96.6%, P=0.067). Isolated anti-HBc-positive HCWs are rare and most of them respond to vaccination. Anti-HBc testing is not a prerequisite for vaccination. This serology suggests a loss of acquired anti-HBs rather than occult HBV infection. Their reduced immunity to vaccination may be related to old age.