The primary purpose of the original study was to assess whether the protection afforded by the paediatric dose of Epaxal vaccine against hepatitis A was not inferior to the protection afforded by the standard dose of Epaxal. The aim of the follow-up phase was to perform a computer based modelling analysis of the long term protection afforded by the paediatric dose, and to compare this with the standard dose and also with an alternative hepatitis A vaccine (Havrix Junior).

Inclusion Criteria:

Original study:

• Males or females aged >=12 months and 16 years of age at the time of the first vaccination.
• Written informed consent obtained from the subject when applicable and 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.

Follow up phase:

• Subjects enrolled and randomized in the primary study and having received two doses of the study vaccine

Exclusion Criteria:

• 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, this means prednisone, or equivalent, >=0.5 mg/kg/day. Inhaled and topical steroids were allowed.)
• Planned administration/administration of a vaccine not foreseen by the study protocol within 4 weeks prior to the first dose of study vaccine
• Previous vaccination against hepatitis A
• Seropositive for anti-HAV antibodies (>=10 mIU/mL)
• 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