Long-term Immunogenicity of Lived-attenuated Hepatitis A Virus Vaccine Among Healthy Thai Children and Adolescents
试验速览
- 阶段
- 不适用
- 状态
- 进行中（未招募）
- 入组人数
- 60
- 试验地点
- 2
- 主要终点
- Anti-HAV seropositivity rate
研究概览
简要总结
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.
详细描述
Hepatitis A virus (HAV) infection remains one of the most common causes of viral hepatitis among children and adolescents in developing countries, including Thailand. The virus is primarily transmitted through the ingestion of contaminated food or water, or through direct contact with an infected person. HAV typically causes acute hepatitis, ranging from mild illness to severe fulminant hepatitis (acute liver failure), but it does not lead to chronic liver disease. Vaccination is a highly effective strategy to prevent HAV infection and its serious complications.
Currently, two types of HAV vaccines are available in Thailand: (1) the inactivated HAV vaccine (I-HAV), which is administered in two doses six months apart and is approved for use in children aged 12 months and older; and (2) the live-attenuated HAV vaccine (L-HAV), administered as a single dose and approved for children aged 18 months and older. However, neither vaccine has been included in Thailand's Expanded Programme on Immunization (EPI), resulting in suboptimal vaccination coverage across the country.
In 2024, the investigators conducted a randomized, active-controlled, open-label, non-inferiority trial to compare the immunogenicity and safety of the two-dose I-HAV regimen with the single-dose L-HAV in healthy Thai children and adolescents aged 18 months to 18 years. The present study aims to assess the long-term seropositive rate and immunogenicity of anti-HAV antibodies among these participants following a single dose of L-HAV.
研究设计
- 研究类型
- Observational
- 观察模型
- Case Only
- 时间视角
- Cross Sectional
入排标准
- 年龄范围
- 18 Months 至 20 Years（Child, Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •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
排除标准
- •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
结局指标
主要结局
Anti-HAV seropositivity rate
时间窗: 1 year after L-HAV vaccination
Anti-HAV seropositivity rate following a single L-HAV vaccine
Anti-HAV antibody level
时间窗: 1 year after L-HAV vaccination
Geometric mean concentration (GMC) of anti-HAV antibodies following a single L-HAV vaccine
次要结局
未报告次要终点
研究者
Tavitiya Sudjaritruk
Associate Professor
Chiang Mai University