Factors Associated with the Presence of Isolated Antibody to Hepatitis B Core Antigen (anti-HBc) and Hepatitis C Antibody (HCV) among Drug Users in Methadone Maintenance

The relationships between HCV and the immunologic response to HBV and the presence of isolated anti-HBc are unclear. Methods: Drug users(DUs)were recruited from two methadone programs for HAV, HBV, HCV testing as part of a RCT to promote adherence to hepatitis services. Associations with isolated anti-Hbc and positive HCVAb were identified. Results: Baseline serologies were available from 321 participants(182 from NYC; 139 from SF). The mean age was 46; 68% males and one transgender. 30% were black, 37% white, 33% Hispanic. 25% had a history of IDU. 14% of subjects were HIV-1 positive of whom 83% had histories of IDU. Overall, 63% had positive HCVAb, 40% were HAV susceptible, 32% were HBV susceptible, 18% were HBV immune by vaccination, 33% were immune by disease, 1% had active HBV, and 17% had isolated anti-HBc. Participants with isolated anti-HBc were more likely than those with other HBV serologies to be HCVAb positive(96% vs. 4%; P<0.0001), older(mean age 52 yrs vs. 45 yrs; P<0.0001) and more frequently had histories of IDU(52% vs. 69%; P=0.06). Factors associated with HCVAb included IDU(91% vs. 9%; P<0.0001), older age(mean age 49yrs vs. 42yrs; P<0.0001), positive HAV(75% vs. 25%; P<0.0001), isolated anti-HBc(24% vs. 1.7%; P<0.0001) and HIV(P=0.06). Conclusion: 32% and 40% of participants respectively were susceptible to HBV and HAV reinforcing the need for vaccination efforts. While isolated anti-HBc has thought to reflect HBV infection with loss of anti-HBs over time, the association of isolated anti-HBc with HCV suggests a possible role for HCV on anti-HBc retention.