Hepatitis A vaccination and immunological parameters in HIV-infected patients

Vaccination against hepatitis A is an important intervention to prevent disease in HIV-patients. There are insufficient data on the association of the response to hepatitis A vaccine with immunological parameters, including subpopulations of T-cells. We studied HIV-infected adults with CD4 T-cells>200 cells/mm(3) who received two doses of hepatitis A vaccine (Havrix or Vaqta). The counts of CD3, CD4, CD8, CD4+T-cells, NK, NK CD8+, NK CD8 - cells, and HIV RNA were measured at the time of first dose administration and one month after the end of the vaccination period. The geometric mean titer of antibodies to hepatitis A virus (anti-HAV) and factors affecting response were evaluated. 113 patients (50 antiretroviral treatment-naïve and 63 treatment-experienced) were enrolled in the study. There was no change in the immunological parameters and in the HIV-RNA post-vaccination, except for a decrease in CD8 and in double positive CD4+CD8+t-cell count. The immune response and geometric mean titer of anti-HAV were similar among treated and naïve patients (78% vs. 76% and 237 mIU/mL vs. 158 mIU/mL). Vaccine response was achieved in 71% of patients with CD4=200-499 cells/mm(3) compared with 80% of participants with CD4 ≥500 cells/mm(3) (p>0.05). Logistic regression revealed that immunological cells tested do not affect response differently in treatment-naïve vs. experienced patients. The only factor affecting response is the CD4 T-cell count at vaccination (OR 1.320; 95% CI 1.052-1.656; p=0.016). Patients with CD4 T-cell count ≥500 cells/mm(3) were 4.3 times more likely to respond to the vaccine than patients with CD4 T-cell count 200-499 cells/mm(3) (p=0.005). In conclusion, successful vaccination is associated with CD4 T-cells. The count of other immune cells or the administration of antiretroviral therapy does not predict response to hepatitis A vaccine in HIV patient with baseline CD4 T-cell>200 cells/mm(3).