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.
History of any reaction or hypersensitivity likely to be exacerbated by any component of the study interventions, including hypersensitivity to neomycin or, gelatin.
Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination.
Hypersensitivity to latex.
Unstable chronic conditions as determined by medical history and physical examination.