The purpose of this study is to evaluate the immunogenicity and safety after one primary dose and one additional dose of inactivated hepatitis A vaccine are administered in Korean healthy children aged 12-23 months.

The objective of this study is to evaluate the immunogenicity and safety after one primary dose and one additional dose (administered twice in total at an interval of 6 months) of inactivated hepatitis A vaccine are administered in Korean healthy children aged 12-23 months.

For this, a two-group comparison study will be conducted using a previously approved inactivated hepatitis A vaccine (Havrix Inj., manufactured by GSK) as the control vaccine to prove that the immunogenicity of the test vaccine treatment group is not inferior to the control vaccine treatment group and to statistically confirm that there is no difference in safety.

Inclusion Criteria:

• A child whose parents or representative provided written consent
• A Korean child aged 12-23 months on the day of the first vaccination
• No history of hepatitis A or a having hepatitis A vaccination
• A child who was determined by the investigator that there is no problem with the participation in the clinical study according to the medical history and physical examination results

Exclusion Criteria:

• Tympanic temperature of 38℃ or above within 48 hours prior to the vaccination or on the day of vaccination
• Moderate to severe acute or chronic infectious disease on the day of vaccination
• History of sensitivity to the following drugs: neomycin, formaldehyde, gentamicin sulfate, any preventive vaccines
• Disorders in the immune system, or congenital or acquired immunodeficient diseases
• Received immunosuppressive dose of systemic corticosteroids therapy within 12weeks days before vaccination
• A child with uncontrolled epilepsy or neurological disorders
• Planned with other vaccine within 4 weeks after the vaccination date
• Administered with other vaccine within 4 weeks prior to the vaccination date
• Used immunoglobulin formulation or human plasma, or received a transfusion within 12 weeks prior to the vaccination date
• A child who has participated or is participating in another clinical trial within 12 weeks prior to the vaccination date(systemic corticosteroids administered at doses corresponding to ≤0.5 mg/kg/day of prednisolone for 14 consecutive days or less is exceptionally allowed)
• Other reasons not specified above that, in the opinion of the investigator, may make the subject ineligible to participate in the study