Immune response to hepatitis B vaccination in HIV-positive individuals with isolated antibodies against hepatitis B core antigen: Results of a prospective Italian study

BACKGROUND AND AIM: Antibodies against hepatitis B core antigen (anti-HBc) are found in 14–44% of patients with HIV infection, but it is still unclear whether hepatitis B virus (HBV) vaccination should be recommended for HIV-positive subjects with isolated anti-HBc (IAHBc). We examined the rate of anamnestic and primary responses (ARs and PRs) and associated factors in a group of HIV-infected patients with an IAHBc profile. METHODS: This prospective study recruited 25 HIV-positive patients with anti-HBc alone who were vaccinated against HBV infection. Those without an AR (anti-hepatitis B envelope antigen [anti-HBs] levels of <10 U/L) or who were hypo-responsiveness (anti-HBs levels of >10 but <100 U/L) four weeks after the first dose of vaccine underwent a full course of vaccinations. Their clinical and virological data, including the presence of occult hepatitis B infection (OBI), were evaluated in accordance with the vaccination schedule. RESULTS: Six of the 25 patients (24%) showed an AR, four of whom had anti-HBs levels of <100 U/L. Ten of 19 (52.6%) remaining patients became seroprotected after the third dose. OBI was detected in four of the six patients with an AR, two of the 10 patients with a PR, and none of the nine patients who did not respond. Multivariate analysis showed that an AR was associated with the presence of OBI (P = 0.0162), and a PR was associated with HCV antibody status. (P = 0.0191). CONCLUSIONS: Our data suggest that testing for anti-HBc alone may not be a reliable means of assessing protection from HBV infection in HIV-positive patients. OBI-positive patients may benefit from a single vaccine dose. Anti-HCV serostatus may affect PRs.