Safety and Immunogenicity of an Adjuvanted Herpes Zoster Subunit Candidate Vaccine in HIV-Infected Adults: A Phase 1/2a Randomized, Placebo-Controlled Study

Background. Human immunodeficiency virus (HIV)-infected individuals are at increased risk of herpes zoster (HZ), even in the antiretroviral therapy (ART) era. Because concerns exist about the use of live-attenuated vaccines in immunocompromised individuals, a subunit vaccine may be an appropriate alternative. Methods. This phase 1/2, randomized, placebo-controlled study evaluated the immunogenicity and safety of an investigational HZ subunit vaccine (HZ/su). Three cohorts of HIV-infected adults aged ≥18 years were enrolled: 94 ART recipients with a CD4⁺ T-cell count of ≥200 cells/mm³, 14 ART recipients with a CD4⁺ T-cell count of 50-199 cells/mm³, and 15 ART-naive adults with a CD4⁺ T-cell count of ≥500 cells/mm³. Subjects received 3 doses of HZ/su (50 μg varicella-zoster virus glycoprotein E [gE] combined with AS01B adjuvant) or 3 doses of saline at months 0, 2, and 6. Results. One month after dose 3, serum anti-gE antibody concentrations and frequencies of gE-specific CD4⁺ T cells were higher following HZ/su vaccination than after receipt of saline (P