Immunogenicity 

The safety and immunogenicity of the new vaccine was evaluated in two unpublished studies that are summarized in the package insert. Among 1280 adults (18-55 years old) and 423 adolescents (11-18 years old) who received Menactra, seroconversion rates for serogroups A, C, Y and W-135 measured by serum bactericidal antibody assay were 100%, 99%, 91% and 97% in the adults and 100%, 99%, 98% and 99% in the adolescents. These rates were about the same with Menomune. A study of US children 2-10 years old who received either Menomune or Menactra found that antibody titers were higher for all 4 serogroups in the children who received Menactra