• Meningococcal rSBA titres in group A and group B [ Time Frame: One month after vaccination with meningococcal vaccine 134612 and the first dose of Twinrix. ] [ Designated as safety issue: No ]
• Hepatitis A seroconversion and Hepatitis B seroprotection in group A and group C [ Time Frame: One month after the third dose of Twinrix. ] [ Designated as safety issue: No ]

• 1 m post first vaccination & post third dose: immunogenicity to vaccine antigens
• 7 months after vaccination with 134612: persistence of antibody response to vaccine 134612
• During entire study period: serious and specific adverse events (solicited & unsolicited), events related to lack of meningococcal vaccine efficacy

• Vaccine response to meningococcal antigens in group A and group B [ Time Frame: One month after vaccination with meningococcal vaccine 134612 and the first dose of Twinrix. ] [ Designated as safety issue: No ]
• Anti-meningococcal polysaccharide concentrations in group A and group B [ Time Frame: Prior to and one month after vaccination with meningococcal vaccine 134612 and the first dose of Twinrix. ] [ Designated as safety issue: No ]
• Anti-tetanus toxoid antibody concentration in group A and group B. [ Time Frame: Prior to and one month after vaccination with meningococcal vaccine 134612 and the first dose of Twinrix. ] [ Designated as safety issue: No ]
• Meningococcal rSBA titres [ Time Frame: One month after the third dose of Twinrix in Group A and seven months after vaccination in Group B. ] [ Designated as safety issue: No ]
• Anti-meningococcal polysaccharide concentrations [ Time Frame: One month after the third dose of Twinrix in Group A and seven months after vaccination in Group B. ] [ Designated as safety issue: No ]
• IgG hepatitis A virus antibody concentration in Group A and Group C. [ Time Frame: Prior to first dose of Twinrix and one month after the third dose of Twinrix ] [ Designated as safety issue: No ]
• IgG hepatitis B surface antigen antibody concentration in Group A and Group C. [ Time Frame: Prior to first dose of Twinrix and one month after the third dose of Twinrix ] [ Designated as safety issue: No ]
• Occurrence of solicited local and general symptoms. [ Time Frame: During the 4-day follow-up period after each vaccine dose. ] [ Designated as safety issue: Yes ]
• Meningococcal rSBA titres in group A and group B [ Time Frame: Prior to vaccination with meningococcal vaccine 134612 and the first dose of Twinrix. ] [ Designated as safety issue: No ]
• Occurrence of unsolicited symptoms. [ Time Frame: Up to one month after each vaccine dose. ] [ Designated as safety issue: Yes ]
• Occurrence of specific adverse events of rash, new onset of chronic illness(es), conditions prompting emergency room visits and physician office visits not related to common illnesses and any events related to lack of meningococcal vaccine efficacy. [ Time Frame: Throughout the entire study. ] [ Designated as safety issue: Yes ]
• Occurrence of serious adverse events [ Time Frame: Throughout the entire study. ] [ Designated as safety issue: Yes ]

This study will demonstrate the non-inferiority of GSK Biologicals' meningococcal vaccine 134612 when given in an experimental co-administration versus vaccine 134612 alone and versus the experimental co-administration alone in healthy subjects aged 11 through 17 years. There will be 3 groups in this study.

All subjects of groups A and B will have 4 blood samples taken, all subjects of group C will have 3 blood samples taken.

The Protocol Posting has been updated in order to comply with the FDA Amendment Act, September 2007.

• Biological: Meningococcal vaccine 134612
• Biological: Twinrix

• Experimental: Three doses of Twinrix, first dose given concomitantly with dose of meningococcal vaccine 134612.
• Active Comparator: One dose of meningococcal vaccine 134612
• Active Comparator: Three doses of Twinrix

Inclusion Criteria:

• Subjects who the investigator believes that they and/or their parents/guardians can and will comply with the requirements of the protocol
• A male or female between, and including, 11 and 17 years of age at the time of the first dose of vaccine.
• Written informed consent obtained from the subject/ from the parent or guardian of the subject.
• Healthy subjects as established by medical history and clinical examination before entering into the study.
• Previously completed routine childhood vaccinations to the best of his/her/the parents'/guardians' knowledge.
• If the subject is female and of childbearing potential, she must practice adequate contraception for 30 days prior to vaccination, have a negative pregnancy test and continue such precautions for two months after completion of the vaccination series.

Exclusion Criteria:

• Use of any investigational or non-registered product (drug or vaccine) other than the study vaccine(s) within 30 days preceding the first 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 first vaccine dose.
• Planned administration/ administration of a vaccine not foreseen by the study protocol within one month of the dose of vaccine.
• Previous vaccination with meningococcal polysaccharide vaccine of serogroup A, C, W-135 and/or Y within the last five years.
• Previous vaccination with meningococcal polysaccharide conjugate vaccine of serogroup A, C, W-135 and/or Y.
• Previous vaccination with tetanus toxoid within the last month.
• Previous vaccination with hepatitis A and/or hepatitis B vaccine.
• Seropositivity for hepatitis A IgG, hepatitis B surface antigen, hepatitis B core antibody and/or hepatitis B surface antigen at screening.
• History of hepatitis A, hepatitis B and/or Neisseria meningitidis infection.
• Known exposure to hepatitis A and/or hepatitis B virus within three months preceding the first dose of study vaccine.
• Any confirmed or suspected immunosuppressive or immunodeficient condition (congenital or secondary), including human immunodeficiency virus (HIV) infection, based on medical history and physical examination.
• A family history of congenital or hereditary immunodeficiency, until the immune competence of the potential vaccine recipient is demonstrated.
• History of reactions or allergic disease likely to be exacerbated by any component of either vaccine.
• Major congenital defects or serious chronic illness.
• Acute disease at the time of enrolment.
• Administration of immunoglobulins and/or any blood products within the three months preceding the 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.