The purpose of this study is to evaluate the immunogenicity, safety and reactogenicity of one dose of four different formulations of the MenACWY conjugate vaccine when given to healthy subjects aged 15-19 years. The selection of the best formulation will be based on data obtained up to one month after the vaccine dose.

The study is open. However, the 4 different formulations of GSK's MenACWY conjugate vaccine will be administered in a double-blind manner. Mencevax™ ACWY vaccine will serve as active control. Subjects will receive one vaccine dose only (GSK's MenACWY conjugate vaccine or Mencevax™ ACWY vaccine), and will have 2 blood samples taken, before and one month after vaccination.

Inclusion Criteria:

• Healthy male or female between, and including, 15 and 19 years of age at the time of vaccination.
• Subject with previously completed routine childhood vaccinations to the best of his/her knowledge or his/her parents'/guardians' knowledge.
• Female subjects should be of non-childbearing potential.

Exclusion Criteria:

• Previous vaccination against OR history of OR exposure within previous 12 months to meningococcal serogroup A, C, W-135 or Y disease.
• Administration of a tetanus vaccine within 6 months before study vaccination.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection.
• A family history of congenital or hereditary immunodeficiency.
• History of any neurologic disorders or seizures.

Patient-level data for this study will be made available through www.clinicalstudydatarequest.com following the timelines and process described on this site.