Measles-Mumps-Rubella+Chickenpox Vaccine

The purpose of this study is to evaluate how consistently 3 different manufacturing lots of the GSK's investigational measles, mumps, rubella, and varicella (MMRVNS) vaccine will produce an immune response. It will also compare the overall immune response to the MMRVNS vaccine with that of the Merck licensed measles, mumps, rubella, and varicella (MMRV) vaccine. The vaccines will be given as a second dose to children aged 4 to 6 years who have previously received a first dose of any combination of measles, mumps, rubella, and varicella-containing vaccine(s). The study will also assess the immune response and safety of the MMRVNS and MMRV vaccines when given at the same time as a diphtheria, tetanus, acellular pertussis, and inactivated poliovirus (DTaP-IPV) vaccine. The DTaP-IPV vaccine used is licensed as Kinrix in the United States.

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).