The purpose of this study is to determine the immunity (the body's protection) against shingles after receiving two doses of an investigational vaccine or placebo (a look alike vaccine with no active ingredients).

The duration of treatment is 12 weeks.

Inclusion Criteria:

• Individuals who are at least 60 years of age with a history of varicella (shingles)
• Females must have been postmenopausal.

Exclusion Criteria:

• Subjects who did not previously participate in the main study of this protocol.
• Subject had shingles since their 6 month follow-up visit in main phase of study.