Both the incidence and severity of herpes zoster (HZ) or shingles increase markedly with increasing age due to a decline in varicella zoster virus (VZV) specific immunity. Considerable evidence further shows that psychosocial stresses salient in the older adult correlate with impairments of cellular immunity. Moreover, our preliminary data indicate that the presence of depressive symptoms in older adults is associated with a declines of VZV responder cell frequency (VZV-RCF) and response to VZV vaccination. Taken together, the untoward effects of age and depressive symptoms on VZV immunity raise the question as to whether a behavioral intervention might augment VZV specific immunity in the older adult. We have preliminarily shown that administration of a relaxation-response based intervention, Tai Chi Chih (TCC), results in improvements in health functioning and VZV immunity in older adults as compared to a control group. TCC is a slow moving meditation comprised of twenty separate standardized movements for use in elderly populations. In this controlled trial, we aim to 1) determine whether the practice of TCC for 16 weeks influences unstimulated- and vaccine-stimulated VZV specific immunity in adults 60 years of age and older; 2) demonstrate that TCC can produce significant changes in psychological adaptation, health behaviors, and health functioning and well-being; 3) assess whether changes in psychological adaptation, health behaviors, and health functioning correlate with changes in VZV immunity following TCC in older adults. We hypothesize that this behavioral intervention that prioritizes treatment of excessive physiological arousal can influence one's affective state with effects on cellular immunity. By standardization of training and practice schedules, TCC offers an important advantage over prior relaxation response based therapies. Focus on older adults at increased risk for HZ, assay of VZV specific immunity, and evaluation of an integrated in vivo immune response has implications for understanding the impact of behavioral factors and a behavioral intervention on a clinically relevant endpoint and response of the immune system to infectious pathogens.