Immunogenicity and Safety of an Investigational Quadrivalent Meningococcal Conjugate Vaccine in Adults 56 Years and Older

The aim of the study was to demonstrate non-inferiority of immunogenicity and evaluate the safety of a single dose of Meningococcal Polysaccharide (Serogroups A, C, Y, and W) Tetanus Toxoid conjugate vaccine (MenACYW conjugate vaccine) compared to a single dose of Meningococcal Polysaccharide Vaccine Serogroups A, C, Y, and W-135 Combined (Menomune® - A/C/Y/W-135) in adults 56 years of age and older in the United States. Primary objective: -To demonstrate the non-inferiority of the vaccine seroresponse to meningococcal serogroups A, C, Y, and W following the administration of a single dose of MenACYW conjugate vaccine compared to those observed following the administration of a single dose of Menomune® - A/C/Y/W-135. Secondary objective: -To compare the serum bactericidal assay using human complement (hSBA) antibody geometric mean titers of meningococcal serogroups A, C, Y, and W following the administration of MenACYW conjugate vaccine to those observed following the administration of Menomune® - A/C/Y/W-135. Observational objectives: * To describe antibody titers against meningococcal serogroups A, C, Y, and W measured by hSBA at baseline (before vaccination) and 30 days after vaccination with MenACYW conjugate vaccine or Menomune® - A/C/Y/W-135 in a subset of 100 participants per treatment group. * To describe the safety profile of MenACYW conjugate vaccine compared to that of the licensed Menomune® - A/C/Y/W-135 after a single administration.