Administration of live varicella vaccine to HIV-infected children with current or past significant depression of CD4+ T cells

Background. Varicella can be a severe illness in human immunodeficiency virus (HIV)-infected children. The licensed, live attenuated varicella vaccine is safe and immunogenic in HIV-infected children with minimal symptoms and good preservation of CD4(+) T cells (Centers for Disease Control and Prevention immunologic category 1). Methods. To study the safety and immunogenicity of this vaccine in varicella-zoster virus (VZV)-naive, HIV-infected children with moderate symptoms and/or more pronounced past or current decreases in CD4+ T cell counts, such children (age, 1-8 years) received 2 doses of vaccine 3 months apart. The children were observed in a structured fashion for adverse events. Blood was tested for VZV antibody and VZV-specific cell-mediated immunity (CMI) at baseline, 8 weeks after each dose, and annually for 3 years. Subjects who had no evidence of immunity 1 year after vaccination received a third dose and were retested. Results. The vaccine was well tolerated; there were no vaccine-related, serious adverse events. Regardless of immunologic category, at least 79% of HIV-infected vaccine recipients developed VZV-specific antibody and/or CMI 2 months after 2 doses of vaccine, and 83% were responders 1 year after vaccination. Conclusions. HIV-infected children with a CD4+ T cell percentage of >= 15% and a CD4+ T cell count of >= 200 cells/mu L are likely to benefit from receiving varicella vaccine.