Response to hepatitis B vaccine in HIV-1-positive subjects who test positive for isolated antibody to hepatitis B core antigen: Implications for hepatitis B vaccine strategies

Background. Whether human immunodeficiency virus type 1 (HIV-1)-positive subjects who test positive for isolated antibody to hepatitis B core antigen (anti-HBc) should be vaccinated with hepatitis B vaccine is not certain. Development of an anamnestic response after vaccination would suggest previous hepatitis B virus (HBV) infection, in which case vaccination is not necessary. Methods. Sixty-nine HIV-1-positive subjects who tested negative for hepatitis B surface antigen ( HBsAg) and antibody to HBsAg (anti-HBs) received vaccination with standard hepatitis B vaccine. Twenty-nine subjects (42%) tested positive for anti-HBc, and 40 (58%) tested negative for anti-HBc. An anamnestic response was defined as an anti-HBs titer of >= 10 IU/L within 4 weeks of the first vaccination. Results. The overall anamnestic response rate was 16% and was not significantly different between subjects who tested positive for anti-HBc (24%) and those who tested negative for anti-HBc (10%) before vaccination (P = .18). Approximately 50% of subjects who tested positive for anti-HBc also tested positive for antibody to hepatitis Be antigen (anti-HBe). The anamnestic response rate was higher in subjects who tested positive for both anti-HBc and anti-HBe (43%) than in subjects who tested positive for anti-HBc but negative for anti-HBe (7%) (P = .035). After a complete series of vaccinations, HIV-1/hepatitis C virus (HCV)-coinfected subjects were less likely to achieve high anti-HBs titers than were subjects infected with HIV-1 alone. Conclusions. After hepatitis B vaccination, the anamnestic response rate in HIV-1-positive subjects who tested positive for isolated anti-HBc but negative for anti-HBe was low and was comparable to that in subjects who tested negative for anti-HBc. This finding suggests that testing for anti-HBc alone may not be a reliable assessment of protection from HBV infection. HIV-1/HCV coinfection may be associated with impaired responses to hepatitis B vaccine, and evaluation of strategies to improve immunogenicity of the vaccine in such individuals is warranted.