• Immunogenicity of IC51 2 months after the first vaccination and HAVRIX® 1440 1 month after the first vaccination
  

• Rate of adverse events, serious adverse events and medically attended adverse events during the vaccination period until 6 months after the last vaccination
  

Inclusion Criteria:

• At least 18 years of age
• In female subjects either childbearing potential terminated by surgery or one year post-menopausal, or a negative serum pregnancy test during screening and the willingness not to become pregnant during the study period and 30 days after the last vaccination by practicing reliable methods of contraception
• Written informed consent obtained prior to study entry

Exclusion Criteria:

• History of clinical manifestation of any flavivirus infection
• History of vaccination against Japanese encephalitis (JE), Yellow fever and Dengue fever (an anti-JEV neutralizing antibody titer >= 1:10 at baseline is acceptable for inclusion, these subjects will be part of the safety population, but will not be analyzed for immunogenicity in the per-protocol analysis)
• History of any previous Hepatitis A vaccination and infection
• Use of any other investigational or non-registered drug or vaccine in addition to the study vaccine during the study period or within 30 days preceding the first dose of study vaccine
• Planned administration of another vaccine during the study period
• Immunodeficiency including post-organ-transplantation or immunosuppressive therapy
• A family history of congenital or hereditary immunodeficiency
• History of autoimmune disease
• Administration of chronic (defined as more than 14 days) immunosuppressants or other immune-modifying drugs within six months of vaccination.
• Any acute infections within 4 weeks prior to enrollment
• Infection with HIV, Hepatitis B (HBsAg) or Hepatitis C