A Study to Evaluate the Safety and Immunogenicity of the Hepatitis A Virus Vaccine HAVpur in Healthy Young Children

• Seroprotection at Months 6 and 7 [ Time Frame: Months 6 and 7 ] [ Designated as safety issue: No ]
  Proportion of subjects seroprotected (>=10 mIU/ml)
• Seroprotection at Months 1, 6 and 7 [ Time Frame: Months 1, 6 and 7 ] [ Designated as safety issue: No ]
  Proportion of subjects seroprotected (>=20 mIU/ml)
• Geometric mean concentrations (GMCs) [ Time Frame: Months 1, 6 and 7 ] [ Designated as safety issue: No ]
  GMCs of anti-HAV antibodies will be measured from blood samples
• Solicited local and systemic adverse events [ Time Frame: For the 4 days following each vaccination ] [ Designated as safety issue: Yes ]
  Proportion of subjects experiencing local and systemic adverse events after primary and after booster vaccination in the two study groups

This is a study to test whether vaccination with HAVpur Junior against hepatitis A provides protection that is non-inferior to the protection afforded by vaccination with Havrix 720 Junior.

• Biological: HAVpur Junior

  ≥12 International Units (IU) hepatitis A antigen coupled to virosomes, intramuscularly (i.m.), anterolateral thigh (M. vastus lateralis) or deltoid (M. deltoideus)

  Vaccination schedule: single doses at 0 and 6 months

• Biological: Havrix 720 Junior

  ≥720 ELISA Units (EU) hepatitis A antigen adsorbed to aluminium hydroxide, intramuscularly (i.m.), anterolateral thigh (M. vastus lateralis) or deltoid (M. deltoideus)

  Vaccination schedule: single doses at 0 and 6 months

• Experimental: HAVpur
  Intervention: Biological: HAVpur Junior
• Active Comparator: Havrix
  Intervention: Biological: Havrix 720 Junior

Inclusion Criteria:

• A male or female between (and including) 18 months to 47 months of age.
• Written informed consent obtained from the parent/legal guardian of the subject.
• Free of obvious health problems as established by medical history and/or clinical examination before entering the study

Exclusion Criteria:

• Seropositive for anti-HAV antibodies (>=10 mIU/ml).
• Use of any investigational or non-registered drug or vaccine within 30 days preceding the first dose of study vaccine, or planned use during the study period and safety follow-up.
• Chronic administration (defined as more than 14 days) of immunosuppressants or other immune-modifying drugs within six months prior to the first vaccine dose (for corticosteroids, such as prednisone, or equivalent, >=0.5 mg/kg/day.
• Inhaled and local steroids are allowed.)
• Planned administration/ administration of a measles containing vaccine within 4 weeks prior to and after the first or booster dose of study vaccine.
• Previous vaccination against hepatitis A.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection.
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine.
• Major congenital defects or serious chronic illness.
• Acute disease at the time of enrolment