Phase 3 Study Comparing Safety and Immune Response of a New Chickenpox Vaccine to Varivax in Healthy Children Aged 12 to 15 Months Receiving a Second Dose 3 Months After the First

What this Trial Is About

This research aims to evaluate the immune response and safety of an investigational chickenpox vaccine VNS Vaccine compared to an already approved vaccine called Varivax VV. The study focuses on healthy children who have not previously had chickenpox or received a chickenpox vaccine, and takes place when the second dose is given three months after the first dose, which is administered between 12 and 15 months of age. Participants are randomly assigned to one of three groups one group receives two doses of the Varivax vaccine another group receives two doses of the investigational VNS vaccine and the third group receives a first dose of Varivax followed by a second dose of the VNS vaccine. Additional vaccines including measles, mumps, and rubella MMR, hepatitis A HAV, and pneumococcal conjugate vaccine PCV are given on the first day. In some countries, a second dose of MMR is also given between 15 and 18 months according to national guidelines. During the study, researchers will monitor immune responses by measuring specific antibodies against the chickenpox virus after the second dose, particularly 43 days post-vaccination. They will also track any local or systemic side effects following each vaccine dose, recording adverse events up to nearly nine months after the first dose. The total participation includes multiple visits over this time, ensuring detailed safety and immune response assessment for each child.

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