Safety and immunogenicity of a live attenuated varicella vaccine in VZV-seropositive HIV-infected adults.

Background: Herpes-zoster is common in HIV-infected patients in spite of antiretroviral therapy. We evaluated the safety and immunogenicity of a live attenuated varicella-zoster virus (VZV) vaccine as a candidate for protecting HIV-infected adults against herpes-zoster.

Results: Sixty-seven HIV-infected and 15 uninfected subjects, 18 to 65 years old, were enrolled. Adverse events were minor and similar in HIV-infected vaccine and placebo recipients. At 12 weeks after the 2(nd) dose of vaccine the magnitude of each measure of VZV CMI increased significantly in healthy controls. In HIV-infected vaccinees, VZV RCF significantly increased and ELISPOT showed a positive trend. None of VZV CMI measures significantly increased in HIV-infected placebo recipients. The immunogenicity of the vaccine did not correlate with the nadir CD4 cells of HIV-infected subjects.

Methods: HIV-infected adults with CD4 > or = 400 cells/microL and plasma HIV RNA <1,000/mL were randomly assigned to receive two doses of VZV vaccine or placebo 12 weeks apart. HIV-uninfected age-matched controls also received two doses of vaccine. VZV-specific cell-mediated immunity (CMI) was measured at baseline and after vaccination using responder cell frequency (RCF), lymphocyte proliferation, and IFNgamma ELISPOT.

Conclusions: Two doses of varicella vaccine were safe in HIV-infected subjects with CD4 > or = 400 cells/microL, but were only modestly immunogenic.