[Possibility of prevention of herpes zoster by use of varicella vaccine].

It has been considered that a decline in specific cell-mediated immunity (CMI) for the varicella-zoster virus (VZV) could be responsible for a high incidence of herpes zoster in the elderly. If the strength of CMI for VZV could be increased by immunization of the elderly with a varicella vaccine, herpes zoster might be preventable. We compared the CMI for VZV (using a lymphoproliferative assay and a varicella skin test) and VZV-IgG antibodies in serum before and after 2-3 months of vaccination in 15 subjects more than 40 years old. When the CMI for VZV was measured by the lymphoproliferative assay, a stimulation index (SI) of more than 2.0 was estimated to be positive in this study. The SIs (mean +/- SD) before and after the vaccination were 2.7 +/- 1.8 and 2.7 +/- 1.9, respectively, and no significant difference was noted. On the other hand, the diameter of erythema in the varicella skin test after the vaccination became larger than that before the vaccination in the 10 of 13 subjects. In addition, serum VZV-IgG antibodies increased after vaccination in 6 of 14 subjects. There were no obvious reasons for the discrepancy in the results of the lymphoproliferative assay and the varicella skin test. However, because of the poor response indicated by the assay, only one vaccination for the elderly might not be enough to increase the CMI for VZV. The appropriate age for vaccination should also be considered. Lastly, further investigation of the CMI for VZV before and after vaccination on larger scale is required.