New immunization recommendations in the US include vaccination of adolescents against pertussis and meningococcal disease. The Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention recommends that Tdap (Tetanus Toxoid, Reduced Diphtheria Toxoid And Acellular Pertussis Vaccine Adsorbed) and MCV4 (Meningococcal conjugate vaccine against serotypes A, C, Y and W-135) vaccines be administered to adolescents at the same office visit if vaccination with both vaccines is indicated. Therefore, this study is designed to evaluate the safety and immunogenicity of a booster vaccination with Boostrix co-administered with Menactra as compared to the administration of either vaccine alone in healthy adolescents 11 - 18 years of age.