Study of a Tetravalent Meningococcal Diphtheria Toxoid Conjugate Vaccine in Toddlers 9 to 18 Months of Age

Inclusion Criteria : * Aged either 9, 12, 15 or 18 months of age or 3 to \< 6 years of age on the day of inclusion. * Informed consent form that has been approved by the site's Institutional Review Board (IRB) and signed by the parent or legal guardian * Able to attend all scheduled visits and to comply with all trial procedures Exclusion Criteria : * History of a serious chronic disease that could interfere with trial conduct or completion. * Known or suspected impairment of immunologic function. * Acute medical illness with or without fever within the last 72 hours, or rectal temperature ≥ 100.4°F (≥ 38.0°C) or axillary temperature ≥ 99.4°F (≥ 37.4°C) on the day of inclusion. * History of invasive meningococcal disease (confirmed either clinically, serologically or microbiologically) or previous meningococcal vaccination. * Administration of immune globulin or other blood products within 3 months, or oral or parenteral corticosteroids or other immunosuppressive therapy within the last 6 weeks of the study vaccine. Individuals on a tapering dose schedule of oral steroids lasting \< 7 days may be included in the trial as long as they have not received more than one course within the last two weeks prior to enrollment. * Antibiotic therapy within the 72 hours prior to having any blood sample drawn. * Received or scheduled to receive any vaccine in the 28-day period prior to receipt of either dose of the study vaccine, or scheduled to receive any vaccination other than influenza vaccination and hyposensitization therapy in the 28-day period after receipt of either dose of the study vaccine. Hyposensitization therapy and influenza vaccination may be received up to two weeks before or after receiving the trial vaccine. * Suspected or known hypersensitivity to any of the vaccine components or history of a life-threatening reaction to the trial vaccine or a vaccine containing the same substances. * Thrombocytopenia or a bleeding disorder contraindicating intramuscular vaccination * Unable to attend one or more of the scheduled visits or to comply with the study procedures. * Participation in another clinical trial in the 4 weeks preceding enrollment. * Planned participation in another clinical trial during the present trial period. * Any condition which, in the opinion of the investigator, would pose a health risk to the subject or interfere with the evaluation of the vaccine.