Cytokine Production and Immunity to Varicella Zoster Virus (VZV) in Elderly Recipients of Zoster Vaccine

After immunization, particularly in older persons, some people are protected from disease by a vaccine and others are not. The investigators believe that this variable response may be due to overproduction of molecules that suppress development of immunity (antibodies and cell mediated immunity). Normally, these molecules are produced to make sure that immunity is regulated in just the right way for the body as a whole, and to prevent autoimmune disease. However, with aging, the immune system may have difficulty in proper immune regulation. Over production of immunosuppressive molecules after vaccination may interfere with the effects of a vaccine. For example when elderly individuals are immunized against zoster with a licensed vaccine, Zostavax, the vaccine is effective in only about 50 to 60%. The investigators will compare blood levels of antibodies, cellular immunity, and immunosuppressive molecules in recipients of Zostavax to see if there is a correlation between development low immunity and high levels of immunosuppressive molecules.