Effect of high dose vitamin D supplementation on subsequent immune responses to administration of the live herpes zoster vaccine to long-term care residents.

Thirty-three long-term care residents (mean age 76.5 years), who were participating in a study in which they were randomized to receive either oral daily standard dose (400-1000 IU/day) 25-hydroxy vitamin D (vitamin D3) (SD) or high dose (3000-4000 IU/day) (HD) vitamin D3, were vaccinated with the live, attenuated herpes zoster vaccine. Blood was drawn at vaccination and three weeks later to determine varicella-zoster virus (VZV) antibody and T-cell mediated immune responses. ELISA and neutralizing antibodies increased significantly, but to the same extent, in both groups. The antibody avidity significantly increased from pre- to post-vaccination only in the HD group. VZV-CMI, as measured by FLUOROSPOT significantly increased post-vaccination in both groups, but the difference in interferon-γ spot-forming cells (SFC) and interleukin-2 SFC was lower in the HD than SD group. The increase in VZV-CMI correlated inversely with circulating regulatory T cells in the HD group. We conclude that pre-treatment with HD vitamin D3 does not appreciably enhance the antibody response to a live vaccine and that VZV-CMI responses were diminished in HD vitamin D3 recipients.