Vi-DT Typhoid vaccine is a novel vaccine. This study will be done to know the long-term protection and persistent antibody by measured the antibody titer after 2,3,4 and 5 years after immunization.

This study will be done to know the long-term protection and persistent antibody, by measured the antibody titer after 2,3,4 and 5 years after immunization.

Inclusion Criteria:

• Healthy.
• Subject who completed the phase II Vi-DT study (Typhoid 0218)
• Subjects/Parents have been informed properly regarding the study and signed the informed consent form.
• Subject/parents/legal guardians will commit to comply with the instructions of the investigator and the schedule of the trial.

Exclusion Criteria:

• Subject concomitantly enrolled or scheduled to be enrolled in another trial.
• Evolving mild, moderate or severe illness, especially infectious diseases or fever (axillary temperature ≥ 37.5oC).
• Known history of allergy to any component of the vaccines.
• History of uncontrolled coagulopathy or blood disorders contraindicating intramuscular injection.
• Any abnormality or chronic disease which according to the investigator might be compromised by the vaccination and/or interfere with the assessment of the trial objectives.