Immunogenicity and Safety of I-HAV in Healthy Thai Children and Adolescents Lacking Protective Antibody After L-HAV

Launched by CHIANG MAI UNIVERSITY · May 10, 2025

Keywords

ClinConnect Summary

This clinical trial is looking at the safety and effectiveness of a hepatitis A vaccine called I-HAV in healthy Thai children and adolescents. The study focuses on those who received a single dose of another vaccine, L-HAV, but did not develop enough protective antibodies against the hepatitis A virus. The goal is to see if an extra dose of I-HAV can help these children build immunity to the virus.

To be eligible for this study, participants must be Thai children and adolescents who previously took part in a related study and received the L-HAV vaccine within the last year but still lack protective antibodies. Participants will need consent from themselves or their caregivers to join. Throughout the trial, participants can expect to receive the I-HAV vaccine, and researchers will monitor their health and any reactions to the vaccine. It's important to know that individuals with certain health conditions or recent illnesses can't participate, ensuring the safety of everyone involved.

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • Thai children and adolescents who previously participated in the previous RCT study
• • Previously randomized to receive one dose of L-HAV vaccine within the past 1 year (+/- 2 months)
• • Have not demonstrate a seropositivity against HAV (anti-HAV IgG \<1 S/CO) at 1 month after L-HAV vaccination
• • Participants and/or caregivers gives written inform consent/assent form
• Exclusion Criteria:
• • History of acute illness within 4 weeks prior to study enrollment
• • Has a history of illness or a diagnosis consistent with hepatitis A after receiving the live attenuated hepatitis A vaccine as part of participation in a previous research study
• • Has a history of receiving any additional hepatitis A vaccine after participating in the previous research study
• • Presence of fever (body temperature ≥38.0°C), jaundice, or yellowing of the eyes within 4 weeks prior to study enrollment
• • Has underlying conditions including thrombocytopenia, coagulopathy, hemophilia A or B, neurological disorders, immunodeficiency disorders, chronic liver disease, or chronic hepatitis B or C infection
• • Has received immunosuppressive agents, immunomodulatory agents, or high-dose corticosteroids (greater than 2 mg/kg/day or more than 20 mg/day) for more than 14 consecutive days within 6 months prior to study enrollment
• • Has received blood products or blood components, including immunoglobulins, within 6 months prior to study enrollment
• • Has received other live vaccines within 30 days prior to study enrollment
• • Has history of allergy to vaccines or any vaccine components, such as aluminum hydroxide, 2-phenoxyethanol, neomycin, formaldehyde, or gentamicin sulfate, or has history of severe allergic reactions (e.g., anaphylaxis) to any vaccines
• • Women planning for pregnancy, pregnant women or lactating women
• • Women in childbearing age who cannot use contraceptive methods during study participation
• • Is concurrently involved in other clinical trials in which receiving an investigational vaccine or study drug as part of study participation
• • Have any condition that, in the opinion of the site investigator, would compromise the subject's ability to participate in the study