A clinical trial to study safety and immunogenicity of two Hepatitis A vaccines in healthy young children aged between, and including, 18 months to 47 months, using a 0/6 month immunization schedule

INTERVENTION: Intervention1: Hepatitis A antigen: 0.25 ml single dose to receive on Day 1 and at Month 6 Control Intervention1: Hepatitis A viral antigen: 0.5 ml single dose to receive on Day 1 and at Month 6 CONDITION: Seroprotection against Hepatitis A PRIMARY OUTCOME: The Primary Endpoint is proportion of subjects seroprotected at Month 1 (seroprotection defined as Anti‐HAV Antibody concentration >/= 10mIU/ml)‐‐‐‐‐‐Timepoint: Seroprotection at month 1 SECONDARY OUTCOME: Proportion of subjects seroprotected (>/= 10mIU/ml) at months 6 and 7; ; Proportion of subjects seroprotected (>/= 20mIU/ml) at months 1,6 and 7; ; GMCs at months 1, 6 and 7‐‐‐‐‐‐Timepoint: #seroprotection (>/= 10mIU/ml) at months 6 and 7; #seroprotected (>/= 20mIU/ml) at months 1,6 and 7 and ; #GMCs at months 1, 6 and 7; ; ; INCLUSION CRITERIA: 1. A male or female between (and including) 18 months to 47 months of age. 2. Written informed consent obtained from the parent/legal guardian of the subject. 3. Free of obvious health problems as established by medical history and/or clinical examination before entering the study.