Not Yet RecruitingNot Applicable

Long-term Immunogenicity of L-HAV Vaccine Among Healthy Thai Children and Adolescents

Thailand60 participantsStarted 2025-06-22

Plain-language summary

Hepatitis A virus (HAV) remains a common infection among Thai children. Two types of HAV vaccines are available in Thailand: an inactivated vaccine (I-HAV, administered in two doses 6 months apart) and a live-attenuated vaccine (L-HAV, administered as a single dose). However, neither vaccine is currently included in Thailand's Expanded Programme on Immunization (EPI). In 2024, a randomized, active-controlled, open-label, non-inferiority trial was conducted to compare the immunogenicity and safety of the two-dose I-HAV with the single-dose L-HAV in healthy Thai children and adolescents aged 18 months to 18 years. This study aims to evaluate the long-term seropositive rate and immunogenicity of anti-HAV antibodies in this population following a single dose of L-HAV.

Who can participate

Age range18 Months – 20 Years

SexALL

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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

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 (+/- 3 months) * 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 * Have any condition that, in the opinion of the site investigator, would compromise the subject's ability to participate in the study

What they're measuring

Anti-HAV seropositivity rate

Timeframe: 1 year after L-HAV vaccination

Anti-HAV antibody level

Timeframe: 1 year after L-HAV vaccination

Trial details

NCT IDNCT07032610

SponsorChiang Mai University

Sponsor typeOTHER

Study typeOBSERVATIONAL

Primary completion2025-08-31

Contact for this trial

Tavitiya Sudjaritruk, MD, PhD

+66-53-936471 tavitiya.s@cmu.ac.th