OBJECTIVETo compare the antibody response between adults with hepatitis B virus (HBV) core antibody (anti-HBc) single positivity and healthy adults after primary immunization and revaccination of hepatitis B vaccine(HepB).

METHODSAdults aged from 18 to 49 who were both negative for HBV surface antigen (HBsAg) and antibody to HBsAg (anti-HBs), but positive for anti-HBc and narrated no history of HepB immunization by themselves, were selected as single anti-HBc positive group ('anti-HBc alone'). Adults who were negative for HBsAg, anti-HBs and anti-HBc, with age differences within 2 years, and same gender under the 1 : 1 matching program, were selected to form the control group. Both groups were vaccinated on 0-1-6 schedule with the same HepB. Those who were non-response to HepB at primary immunization were revaccination on 0-1-6 schedule. Response rates and geometric mean concentrations (GMC) between the two groups were compared.

RESULTSIn total, the number of anticipants were 228 pairs. Rates on non-response, low-response, normal-response and high-response after the primary immunization were 8.77% , 11.84%, 31.14% and 48.25% in the control group respectively. The corresponding rates were 8.33%, 30.70%, 35.96% and 25.00% in the 'anti-HBc alone'. The rate of low-response in the control group was lower than that in the 'anti-HBc alone' (χ(2) = 22.28, P < 0.01), while the rate of high-response was higher than that in the control group (χ(2) = 24.43, P < 0.01). GMC of anti-HBs in the control group (534.07 mIU/ml) was higher than that in the 'anti-HBc alone' (183.99 mIU/ml) (u = 4.42, P < 0.01). The anti-HBs conversion rates were 82.35% and 41.18% in the control group and in the 'anti-HBc alone' respectively after the first-dose revaccination, but increased to 90.00% and 82.35% after the third-dose revaccination. The anti-HBs conversion rates in the control group were higher than that in the 'anti-HBc alone' after the first-dose revaccination (P < 0.05), while there was no difference seen between the two groups after the third-dose revaccination (P > 0.05).

CONCLUSIONImmune response in the anti-HBc positive adults after primary immunization was weaker than that in common adults. However, immune response induced by HepB was enough to prevent them from infecting HBV. The rates of response showed an obvious increase after revaccination, hence the same HepB immunization strategy could be used.