Live Zoster Vaccine in HIV-Infected Adults on Antiretroviral Therapy

• Number of Participants With Composite Safety Endpoint of the Occurrence of Serious Adverse Events (SAEs) or Division of AIDS (DAIDS) Grade 3 and 4 Signs and Symptoms, Excluding SAEs Related to Trauma [ Time Frame: During the 6 week study period after receipt of any dose of ZOSTAVAX ] [ Designated as safety issue: Yes ]
  Although the study was designed as a randomized trial, it was not powered to detect safety related differences between treatment arms. The safety of ZOSTAVAX was determined by comparing the number of subjects from the active arm who experienced safety endpoint to the number from a pre-specified decision rule, which was calculated based on a similar population and calibrated using the number of safety endpoints observed from the placebo arm. The pre-specified decision rule is that ZOSTAVAX would be considered to have acceptable safety if no more than 18 subjects experience a study-defined composite safety endpoint.
  
  

• VZV Antibodies as Measured by gpELISA [ Time Frame: Within 6 weeks following one or two doses of ZOSTAVAX ] [ Designated as safety issue: No ]
  VZV antibody titer measured by gpELISA after one or two doses of ZOSTAVAX/placebo
  
  
• VZV-specific Cellular Immune Responses by Intracellular Cytokine Staining and/or ELISPOT Assays in the First 40 Subjects Entering in Each CD4 Stratum at the Opening of Stage II [ Time Frame: Within 6 weeks following one or two doses of ZOSTAVAX ] [ Designated as safety issue: No ]
  

The varicella-zoster virus (VZV) which causes herpes zoster (HZ), or shingles, is associated with a painful skin rash and post-herpetic neuralgia (PHN). The incidence and severity of HZ and PHN increase as immune function decreases, as in elderly or HIV-infected people. The live VZV vaccine, ZOSTAVAX, has been shown to reduce the incidence and severity of HZ and PHN in people over the age of 60. The main purpose of this study is to determine whether a two-dose regimen of ZOSTAVAX is safe and well-tolerated in HIV-infected individuals with conserved immune function.

This study has two stages and two arms. It may last up to 24 weeks per subject. In Stage 1, 48 participants with CD4 cell counts of 200 or more cells/uL will be enrolled (24 participants with a CD4 count between 200 and 349 cells/uL and 24 participants with a CD4 count equaling 350 or more cells/uL). These participants will be randomized 3:1 to receive two doses of ZOSTAVAX or placebo at least six weeks apart. If certain safety criteria are met for Stage 1, enrollment will be opened to Stage 2. Stage 2 will enroll approximately 352 subjects with CD4+ T cell counts >= 200 cells/uL. In Stage 2, participants will be stratified using the same parameters as Stage 1 and will then be randomized 3:1 to receive either two doses of vaccine or placebo according to the same schedule. Participants will be followed for at least 42 days after each vaccination. Temperatures will be collected daily for 42 days following each vaccination. Telephone contact will also be made 2 to 3 days after each vaccination and at 24 weeks following the initial vaccination to obtain information regarding vaccination-related symptoms.

All participants will have between 6 and 8 study visits. At the screening visit, documentation of HIV status is required, and blood and urine collection, a physical exam, medical history, and clinical assessment will occur. At each visit, a targeted physical exam will occur. At some visits, blood and urine collection, and a clinical assessment will occur. Antiretroviral medications are not provided by this study.