Immunogenicity and Safety of Meningococcal Vaccine GSK134612 vs. Menactra® in Healthy Adolescent/Adults Aged 10-25 Years.

Inclusion Criteria: * Subjects whom the investigator believes can and will comply with the requirements of the protocol. * A male or female between, and including, 10 and 25 years of age (has not attained his/her 26th birthday) at the time of the vaccination. * Written informed consent obtained from parents/guardian of the subject and written informed assent obtained from the subject if the subject is less than 18 years of age, or written informed consent obtained from the subject if the subject has achieved the 18th birthday. * Healthy subjects as established by medical history and clinical examination before entering into the study. * If the subject is female, she must be of non-childbearing potential, or if she is of childbearing potential, she must practice adequate contraception (including abstinence) for 30 days prior to vaccination, have a negative pregnancy test and continue such precautions for 2 months after vaccination. Exclusion Criteria: * Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine(s) within 30 days preceding the dose of study vaccine, or planned use during the study period. * Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within six months prior to the vaccine dose. * Planned administration/ administration of a vaccine not foreseen by the study protocol within one month of the dose of vaccine(s). * Previous vaccination with meningococcal polysaccharide or conjugate vaccine of serogroup A, C W-135, and/or Y. * Previous vaccination with tetanus and diphtheria toxoids within the last month (i.e., Tdap, Td, and TT-containing vaccine within the last month). * History of meningococcal disease due to serogroup A, C, W-135, or Y. * Any confirmed or suspected immunosuppressive or immunodeficient condition (congenital or secondary), including human immunodeficiency virus (HIV) infection, based on medical history and physical examination (no laboratory testing is required). * A family history of congenital or hereditary immunodeficiency, until the immune competence of the potential vaccine recipient is demonstrated. * History of allergic disease or reactions likely to be exacerbated by any component of the vaccine. * Hypersensitivity to latex. * Major congenital defects or serious chronic illness. * History of any neurologic disorders or seizures. * Previous history of Guillain-Barré Syndrome. * Bleeding disorders, such as hemophilia or thrombocytopenia, or subjects on anti-coagulant therapy. * Acute disease at the time of enrollment. * Administration of immunoglobulins and/or any blood products within the three months preceding the first dose of study vaccine or planned administration during the study period. * Pregnant or lactating female. * History of chronic alcohol consumption and/or drug abuse. * Female planning to become pregnant or planning to discontinue contraceptive precautions.