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Hepatitis APhase 3HAV-2NCT06978621

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

A Phase 3 study testing Inactivated hepatitis A vaccine (I-HAV) in people with Hepatitis A and Hepatitis A Virus, run by Chiang Mai University at 1 site in Thailand.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial 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. Read more about this study

Who is it for?
Ages 18 months to 20 yearsHealthy volunteers can take part
What is being tested?
Inactivated hepatitis A vaccine (I-HAV)
Could I receive a placebo?
No, everyone receives an active treatment
How many people
36 participants
Where
1 siteThailand
Study dates
25 May 2025to 31 Jul 2026
Phase
Phase 3
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 months to 20 years
  • All sexes
  • Healthy volunteers accepted
  • Child, Adult

Who may be able to join

  • 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

Who cannot join

  • 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
Show all 13Show fewer
  • 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

Trial locations and contacts

1 site in 1 country.

Thailand1 site

  • Department of Pediatrics, Faculty of Medicine, Chiang Mai University

    Chiang Mai, 50200

Other trials in Thailand

About this study

Official title: Immunogenicity and Safety of Inactivated Hepatitis A Vaccine in Healthy Thai Children and Adolescents Lacking Protective Antibody Levels After a Single Dose of Live-attenuated Hepatitis A Vaccine

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.

Read the detailed description

Hepatitis A virus (HAV) infection remains a common cause of viral hepatitis among children and adolescents in developing countries, including Thailand. Currently, two types of HAV vaccines are available in Thailand; (1) inactivated HAV vaccine (I-HAV) which is recommended as a 2-dose series administered 6 months apart, approved for use in children aged 1 year and older, and (2) live-attenuated HAV vaccine (L-HAV) which is recommended as a single dose, approved for children aged 18 months and older. However, as neither vaccine is included in Thailand's Expanded Programme on Immunization (EPI), the national vaccination coverage remains suboptimal.

In 2024, the investigators conducted a randomized, active-controlled, open-label, non-inferiority trial to compare the immunogenicity and safety of the currently marketed I-HAV and L-HAV in healthy Thai children and adolescents aged 18 months to 18 years. Preliminary results showed that a proportion of participants remained seronegative following a single dose of L-HAV (anti-HAV IgG <1 S/CO). Based on these findings, the investigators hypothesize that an additional dose of I-HAV may be necessary to achieve adequate seroprotection in this population. Therefore, the aim of this study is 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.

Being tested
Inactivated hepatitis A vaccine (I-HAV)
Keywords
Inacitivated hepatitis A vaccine, Safety, Immunogenicity, Clinical trial
Medical subject headings
Hepatitis A, Hepatitis, Vaccine-Preventable Diseases

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Inactivated hepatitis A vaccine (I-HAV)Biological

    A formaldehyde-inactivated hepatitis A virus (HM175 hepatitis A virus strain)

    Dose and administration: 0.5 mL intramuscular injection for participants age <=18 years, and 1.0 mL intramuscular injection for participants age 19 years and above.

Study groups in NCT06978621
Study groupRoleWhat they receive
Inactivated HAV vaccine (I-HAV)ExperimentalAn additional dose of inactivated hepatitis A vaccination for participants who have seronegative (anti-HAV IgG <1 S/CO) at baseline (1 year after a single dose of live-attenuated hepatitis A vaccine).
Receives: Biological: Inactivated hepatitis A vaccine (I-HAV)

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Anti-HAV immunoglobulin G (IgG) seropositivity rate

    Anti-HAV IgG seropositivity rate (anti-HAV IgG >= 1.0 S/CO) before and after an additional dose of I-HAV vaccine.

    Measured: at baseline (1 year after L-HAV vaccination) and 4 weeks after an additional I-HAV vaccination.

  2. Incidence of adverse events following I-HAV vaccination

    Adverse events, including solicited local and systemic reactions as well as serious adverse events, following an additional dose of I-HAV vaccine.

    Measured: immediate and until 4 weeks after an additional I-HAV vaccination.

Secondary outcomes (1)

  1. Geometric mean concentration (GMC) of anti-HAV IgG level

    Geometric mean concentration (GMC) of anti-HAV IgG level before and after an additional dose of I-HAV vaccine.

    Measured: at baseline (1 year after L-HAV vaccination) and 4 weeks after an additional I-HAV vaccination.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted18 May 2025
  2. Study start25 May 2025
  3. Primary completion22 Jun 2025
  4. Study completion31 Jul 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 3
Primary purpose
Prevention
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
36 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06978621
Sponsor's protocol ID
PED-2568-0180
Acronym
HAV-2
Status last verified
May 2026
First submitted
30 Apr 2025
Last updated
22 May 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No: There is not a plan to make individual participant data (IPD) available to other researchers for this study.

Publications

  • Kunanitthaworn N, Mueangmo O, Saheng J, Wongjak W, Lertsiriladakul T, Chaito T, Nantarat P, Sudjaritruk T. Seroprevalence of hepatitis A virus antibodies among children and adolescents living in Northern Thailand: an implication for hepatitis A immunization. Sci Rep. 2023 Oct 13;13(1):17432. doi: 10.1038/s41598-023-44643-0.

    PubMed 37833325

  • Ma F, Yang J, Kang G, Sun Q, Lu P, Zhao Y, Wang Z, Luo J, Wang Z. Comparison of the safety and immunogenicity of live attenuated and inactivated hepatitis A vaccine in healthy Chinese children aged 18 months to 16 years: results from a randomized, parallel controlled, phase IV study. Clin Microbiol Infect. 2016 Sep;22(9):811.e9-811.e15. doi: 10.1016/j.cmi.2016.06.004. Epub 2016 Jun 23.

    PubMed 27345175

  • Liu XE, Wushouer F, Gou A, Kuerban M, Li X, Sun Y, Zhang J, Liu Y, Li J, Zhuang H. Comparison of immunogenicity between inactivated and live attenuated hepatitis A vaccines: a single-blind, randomized, parallel-group clinical trial among children in Xinjiang Uighur Autonomous Region, China. Hum Vaccin Immunother. 2013 Jul;9(7):1460-5. doi: 10.4161/hv.24366. Epub 2013 Apr 9.

    PubMed 23571173

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing Inactivated hepatitis A vaccine (I-HAV) in people with Hepatitis A and Hepatitis A Virus, run by Chiang Mai University at 1 site in Thailand.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 22 May 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in Thailand. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Anti-HAV immunoglobulin G (IgG) seropositivity rate (time frame: at baseline (1 year after L-HAV vaccination) and 4 weeks after an additional I-HAV vaccination.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06978621, which also lists 3 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 May 2026.

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