Objectives
1. To determine the increase in Varicella-zoster virus (VZV)-specific cell-mediated immune response from pre-zoster vaccination to 3 weeks post-vaccination in nursing home residents after 4 months of high dose vs. standard dose vitamin D3 supplementation.
2. In the same participants as Aim 1, to measure the association between pre-zoster vaccination 25-hydroxyvitamin D \[25(OH)D\] levels and the increase in VZV-specific cell-mediated immune response from pre- vaccination to 3 weeks post-vaccination.
3. Characterize the phenotypic and functional VZV-specific T cell responses to Zostavax, including memory, effector, Th1/Th2, and homing receptor-bearing T cells in the high compared to low ELISPOT responders.
Hypotheses
1. At baseline, higher serum 25(OH)D levels will be associated with higher levels of VZV-specific cell-mediated immunity (cross-sectional).
2. At baseline, higher serum 25(OH)D levels, independent of vitamin D supplementation dose, will be associated with greater increases in VZV-specific cell-mediated immune responses to Zostavax, as measured by the interferon (IFN)-γ ELISPOT assay.
3. Compared to standard dose, high dose vitamin D3 supplementation will enhance VZV-specific cell-mediated immune response to vaccination independent of baseline serum 25(OH)D levels.
