Irwin MR, Olmstead R, Oxman MN.

OBJECTIVES: To evaluate the effects of a behavioral intervention, Tai Chi, on resting and vaccine-stimulated levels of cell-mediated immunity (CMI) to varicella zoster virus (VZV) and on health functioning in older adults. DESIGN: A prospective, randomized, controlled trial with allocation to two arms (Tai Chi and health education) for 25 weeks. After 16 weeks of intervention, subjects were vaccinated with VARIVAX, the live attenuated Oka/Merck VZV vaccine licensed to prevent varicella. SETTING: Two urban U.S. communities between 2001 and 2005. PARTICIPANTS: A total of 112 healthy older adults aged 59 to 86. MEASUREMENTS: The primary endpoint was a quantitative measure of VZV-CMI. Secondary outcomes were scores on the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36). RESULTS: The Tai Chi group showed higher levels of VZV-CMI than the health education group (P<.05), with a significant rate of increase (P<.001) that was nearly twice that found in the health education group. Tai Chi alone induced an increase in VZV-CMI that was comparable in magnitude with that induced by varicella vaccine, and the two were additive; Tai Chi, together with vaccine, produced a substantially higher level of VZV-CMI than vaccine alone. The Tai Chi group also showed significant improvements in SF-36 scores for physical functioning, bodily pain, vitality, and mental health (P<.05). CONCLUSION: Tai Chi augments resting levels of VZV-specific CMI and boosts VZV-CMI of the varicella vaccine.