A Phase 3a, Open-Label, Randomized, Controlled Study to Evaluate the Immunogenicity and Safety of Intramuscular Administration of an Investigational Varicella Vaccine and Priorix Compared With Subcutaneous Administration of Varivax and Priorix, When Given as a First Dose to Healthy Children 12 to 15 Months of Age
This study aims to assess the immune response and safety of GSK's candidate chickenpox and marketed MMR vaccines when given to children 12 to 15 months of age via a muscle injection. It compares the GSK vaccines to Merck's chickenpox vaccine, administered just under the skin. Additionally, the study will evaluate the immune response and safety of giving the GSK vaccines along with other childhood vaccines through a muscle injection.
• Participant's parent(s)/ Legally acceptable representatives (LAR\[s\]), who, in the opinion of the investigator, can and will comply with the requirements of the protocol (e.g., completion of the eDiaries, return for follow-up visits).
• Written or witnessed/thumb printed informed consent obtained from the participant's parent(s)/LAR(s) prior to performance of any study-specific procedure.
• Healthy participants as established by medical history and clinical examination before entering into the study.
• A male or female between, and including, 12 to 15 months of age (i.e., from the day of 1-year birthday until the day before 16 months of age) at the time of the administration of study interventions.
• Only for children in countries where PCV is recommended at 12 to 15 months of age as per national immunization schedule and provided as part of the study interventions:
⁃ Participant who previously received the primary series of PCV in the first year of life with last dose at least 60 days prior to the administration of study intervention.