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

Inclusion Criteria: * Aged 2 to 6 years on the day of inclusion * Informed consent form has been signed and dated by the parent or another legally acceptable representative * Subject and parent/ legally acceptable representative are able to attend all scheduled visits and to comply with all trial procedures * Written documentation of immunization history against meningococcal disease according to the national Expanded Program on Immunization (EPI) schedule (including 2 doses with Meningococcal Group A Polysaccharide Vaccine between 6 and 18 months of age). Exclusion Criteria: * Participation in the 4 weeks preceding the trial vaccination or planned participation during the present trial period in another clinical trial investigating a vaccine, drug, medical device, or medical procedure * Receipt of any vaccine in the 4 weeks preceding the trial vaccination or planned receipt of any vaccine in the 4 weeks following the trial vaccination (except for influenza vaccination, which may be received at least 2 weeks before study vaccines) * Previous vaccination against meningococcal disease within the past 12 months with either the trial vaccine or another vaccine * Previous vaccination with any meningococcal conjugate vaccine. * Receipt of immune globulins, blood or blood-derived products in the past 3 months * Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months) * History of meningococcal infection, confirmed either clinically, serologically, or microbiologically * At high risk for meningococcal disease during the trial, including: 1. persons with increased susceptibility such as persistent complement component deficiencies, 2. persons with anatomic or functional asplenia, 3. persons who have exposure (e.g., microbiologists routinely working with N. meningitidis, or travelers to or residents of areas where meningococcal disease is hyperendemic or epidemic) * Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccines used in the trial or to a vaccine containing any of the same substances * Known thrombocytopenia, as reported by the parent/ legally acceptable representative, contraindicating intramuscular vaccination * Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular vaccination * Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily * Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with trial conduct or completion * Moderate or severe acute illness/infection (according to investigator judgment) on the day of vaccination or febrile illness (axillary temperature ≥ 37.1°C). A prospective subject should not be included in the study until the condition has resolved or the febrile event has subsided * Receipt of oral or injected antibiotic therapy within 72 hours before the first blood draw * Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study * Any contraindication as listed in the study vaccines leaflets.