Influence of age and nature of primary infection on varicella-zoster virus-specific cell-mediated immune responses.

BACKGROUND: Varicella-zoster virus (VZV)-specific cell-mediated immunity is important for protection against VZV disease. We studied the relationship between VZV cell-mediated immunity and age after varicella or VZV vaccination in healthy and human immunodeficiency virus (HIV)-infected individuals. METHODS: VZV responder cell frequency (RCF) determinations from 752 healthy and 200 HIV-infected subjects were used to identify group-specific regression curves on age. RESULTS: In healthy individuals with past varicella, VZV RCF peaked at 34 years of age. Similarly, VZV-RCF after varicella vaccine increased with age in subjects aged <1 to 43 years. In subjects aged 61-90 years, VZV RCF after zoster vaccine decreased with age. HIV-infected children had lower VZV RCF estimates than HIV-infected adults. In both groups, VZV RCF results were low and constant over age. Varicella vaccination of HIV-infected children with CD4 levels 20% generated VZV RCF values higher than wild-type infection and comparable to vaccine-induced responses of healthy children. CONCLUSIONS: In immunocompetent individuals with prior varicella, VZV RCF peaked in early adulthood. Administration of varicella vaccine to HIV-infected or uninfected individuals aged >5 years generated VZV RCF values similar to those of immunocompetent individuals with immunity induced by wild-type infection. A zoster vaccine increased the VZV RCF of elderly adults aged <75 years to values higher than peak values induced by wild-type infection.

The use of HAART is associated with decreased risk of death during initial treatment of cryptococcal meningitis in adults in Botswana.

OBJECTIVE: The objective of this study was to evaluate outcomes among adults with a first episode of cryptococcal meningitis (CM), comparing those on highly active antiretroviral therapy (HAART) with those not on HAART. METHODS: We conducted a prospective cohort study among HIV-infected adults (aged 18 years and older) with a first episode of CM at the Princess Marina Hospital, in Gaborone, Botswana. The proportions surviving to discharge were compared. Logistic regression was used to evaluate the relationship between HAART use and risk of death in the hospital, adjusting for potential confounders. RESULTS: Ninety-two patients [median CD4 41 cells/mm (interquartile range 22-85)] were included, 26 of whom were on HAART at the time that they developed CM. The in-hospital mortality was lower among those on HAART {2 of 26 (8%) vs 14 of 66 (21%); odds ratio = 0.36 [95% confidence interval (CI) 0.09 to 1.49]}, and this result was statistically significant after adjustment for male sex and tuberculosis [adjusted odds ratio = 0.19 (95% CI 0.04 to 1.00)]. CONCLUSIONS: HAART use at the time of a first admission with CM is associated with decreased risk of death during the acute phase of disease. Reasons for this association should be explored.