A Study on the Immune Response and Safety of the Second Dose of an Investigational Chickenpox Vaccine When Given to Healthy Children 3 Months After a First Dose at 12 to 15 Months of Age
The purpose of this study is to evaluate the immune response and safety of GSKs investigational varicella vaccine (VNS Vaccine) compared to an already approved varicella vaccine, Varivax (VV), when administered as second dose to healthy children. 3 months after first dose at 12 to 15 months. The study will be conducted in children who have not previously contracted varicella or received a varicella vaccination.