Confirm eligibility Predose lab collection: Interferon-G Enzyme-Linked Immunospot Assay (ELISPOT), GPELISA, VZV Glycoprotein Enzyme-Linked Immunosorbent Assay (also known as Varicella Zoster antibody titre), and Urine pregnancy test for women of childbearing potential Randomize the subject Administer study drug - either Zostavax vaccine or placebo