Study of Sanofi Pasteur and Lanzhou Institute's Meningococcal (Group A and C) Polysaccharide Vaccine in Children

This study is part of the post-licensure commitment to evaluate the safety and immunogenicity of Meningo A+C vaccine in healthy Chinese children 2 to 6 years of age. Primary Objective: To demonstrate the non-inferiority in terms of seroconversion rate for serogroups A and C, 30 days after a single dose of Sanofi Pasteur Meningococcal (Groups A and C) Polysaccharide Vaccine versus Lanzhou Institute for Biological Products Meningococcal (Groups A and C) Polysaccharide Vaccine. Secondary Objective: * To describe the immunogenicity for serogroups A and C, 30 days after administration of the study vaccines given as a single dose. * To describe the full reactogenicity profile after administration of the study vaccines given as a single dose.