Immune response to hepatitis A vaccination in HIV-infected men in Greece.

HIV-infected patients are at increased risk for acquiring hepatitis A virus (HAV) infection. We evaluated the seroconversion rate (anti-HAV antibodies ≥ 20 mIU/ml) and the geometric mean antibody titres (GMTs) in a group of 351 HIV infected men, who had received two doses of a hepatitis A vaccine. We analysed blood samples collected at one, six, 12 and 18 months following the administration of the second dose of the vaccine. The seroconversion rate one month after the second dose of the vaccine was 74.4% (260/351). At month 18 after the end of vaccination, 56.1% of the subjects remained seropositive. GMTs were 315, 203, 153 and 126 mIU/ml at months 1, 6, 12, and 18, respectively. Logistic regression revealed that the CD4 count is the only factor affecting response to vaccination (P = 0.019). A higher response rate and higher GMTs were observed in patients with CD4 counts ≥ 500 cells/mm(3) (76.6%) than in patients with CD4 counts 200-499 cells/mm(3). In conclusion, even in patients with near-normal CD4 counts, the response to the hepatitis A vaccine is impaired.