The Fifth-year Follow-up Study for the Phase IV Clinical Trial of Hepatitis A Vaccine in Healthy Children

The Phase IV, Open-labelled, Follow-up Study to Evaluate the Five-year Immune Persistence of One Injection of Inactivated or Attenuated Alive Hepatitis A Vaccine in Healthy Chinese Children

The purpose of this follow-up study is to evaluate the five-year immune persistence of one injection of inactivated and attenuated alive hepatitis A vaccine in healthy children.

In the previous double-blind, randomized, phase IV clinical trial in 2008, 300 healthy Chinese children aged 18 to 35 months old were administered with one dose of inactivated and attenuated alive hepatitis A vaccine. Series of serum samples were taken for immunogenicity and immune persistence evaluation. Safety observations were performed after vaccination. This trial was also approved by Tianjin CDC Biomedical Ethics Committee in 2008.

This study is the fifth-year follow-up research for the previous clinical trial.

Inclusion Criteria:

• All subjects who received inactivated or attenuated alive HAV vaccine in the previous trial

Exclusion Criteria:

• Subjects who refused to continue in the follow-up study