This is a multi-center, randomized, double blinded, parallel-group study to assess the Immunogenicity and safety of NBP608 compared to Zostavax which are indicated for the prevention of herpes zoster. Total of 646 healthy subjects aged 50 and over are enrolled, and each subject is administered with single dose of vaccine which is randomly assigned to low, high potency of NBP608 group and Zostavax group in 1:1:2 ratio. Stratified randomization for age group is used to achieve the balance of treatment assignment within age strata.