Objectives: The acquisition of adequate vaccine-induced humoral immunity is especially important in HIV-infected individuals, who are at increased risk of infections. The aim of the study was to assess the safety of administering a complete vaccination programme to successfully treated HIV-infected adults and to evaluate specific humoral responses and the effect of highly active antiretroviral therapy (HAART) interruption on these responses.
Methods: A placebo-controlled, double-blind clinical trial was designed and 26 HIV-infected adults enrolled. Study participants were randomized to receive either a complete immunization schedule with commercial vaccines or placebo for 12 months. HAART was then discontinued for 6 months. Specific humoral responses were evaluated at baseline, at month 12 and after HAART interruption and compared between groups.
Results: There were neither local nor systemic secondary effects related to vaccination. Specific humoral responses to vaccines were adequate, but a loss of immunoglobulin G titres was observed after HAART interruption in 12 study participants.
Conclusions: HAART interruption may cause impairment of previously acquired vaccine-induced immunity in HIV-infected adults.