Clinical Trial

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

Study acronym: HAV-2

Active, Not Recruiting Phase 3

Summary

Hepatitis A virus (HAV) remains a common infection in Thai children. Two HAV vaccines are available: inactivated vaccine (I-HAV, 2 doses) and live-attenuated vaccine (L-HAV, single dose), but neither is included in Thailand's national immunization program. Our previous randomized, active-controlled, open-label, non-inferiority trial trial found that some participants remained seronegative after one L-HAV dose (anti-HAV IgG \<1 S/CO) (preliminary data). This study aims to evaluate the immunogenicity and safety of an additional dose of I-HAV in healthy Thai children and adolescents who did not develop protective antibody levels after a single dose of L-HAV.

Protocol Amendment History 3 amendments

This ClinicalTrials.gov record has been amended 3 times since 2025-05-10; most recent amendment 2026-05-19.

Status change: Recruiting → Active, Not Recruiting 2026-05-19

Status change: Not Yet Recruiting → Recruiting 2025-06-13

Trial Details

NCT Number	NCT06978621
Lead Sponsor	Chiang Mai University Collaborators: Faculty of Medicine, Chiang Mai University
Conditions	Hepatitis A, Hepatitis A Virus, Vaccine-Preventable Diseases
Enrollment	36 participants
Start Date	2025-05-25
Primary Completion	2025-06-22 (estimated)
Study Completion	2026-07-31 (estimated)
Updated on ClinicalTrials.gov	2026-05-22