A Phase 3a, Observer Blind, Randomized, Controlled Study to Evaluate the Immunogenicity and Safety of Intramuscular Administration of an Investigational Combined Measles, Mumps, Rubella, and Varicella Vaccine Compared With Intramuscular Administration of ProQuad When Administered as a Second Dose to Healthy Children Aged 15 Months to 6 Years of Age
This study is evaluating the immunogenicity and safety of intramuscular administration of the investigational MMRVNS vaccine compared to intramuscular administration of the MMRV (Merck's measles, mumps, rubella and varicella) vaccine (ProQuad) that is already licensed for this route, when administered as a second dose in children 15 months to 6 years of age who were previously primed with a first dose of any combination of measles, mumps, rubella and varicella-containing vaccine(s).
• Participants' parent(s)/legally acceptable representative(s) (LAR(s)) who, in the opinion of the investigator, can and will comply with the requirements of the protocol.
• Written or witnessed/thumb printed informed consent obtained from the participants parent(s)/LAR(s) prior to performance of any study specific procedure.
• Informed assent obtained from the participants in line with local rules and regulations.
• Healthy participants as established by medical history and clinical examination at screening.
⁃ For countries where the second dose of measles, mumps, rubella, and varicella vaccination is administered between 4 and 6 years of age:
• A male or female participant between and including 4 and 6 years of age at the time of the study intervention administration, and in accordance with local regulations.
• Participant who previously received a first dose of varicella-containing vaccine in the second year of life.
• Participant who previously received a first dose of measles, mumps, rubella-containing vaccine in the second year of life.
⁃ For other countries:
• A male or female participant between and including 15 months to 6 years of age at the time of study intervention administration, and in accordance with local regulations.
• Participant who previously received a first dose of varicella-containing vaccine in the second year of life, or earlier at 11 months of age in accordance with national vaccination schedule following official recommendation, at least 3 months before study entry.
• Participant who previously received a first dose of measles, mumps, rubella-containing vaccine in the second year of life, or earlier at 11 months of age in accordance with national vaccination schedule following official recommendation, at least 1 month before study entry.