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
试验速览
- 阶段
- 3 期
- 状态
- 进行中（未招募）
- 入组人数
- 36
- 试验地点
- 2
- 主要终点
- Anti-HAV immunoglobulin G (IgG) seropositivity rate
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Prevention
- 盲法
- None
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 (+/- 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
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
- •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
研究组 & 干预措施
Inactivated HAV vaccine (I-HAV)
An 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).
干预措施: Inactivated hepatitis A vaccine (I-HAV) (Biological)
结局指标
主要结局
Anti-HAV immunoglobulin G (IgG) seropositivity rate
时间窗: at baseline (1 year after L-HAV vaccination) and 4 weeks after an additional I-HAV vaccination.
Anti-HAV IgG seropositivity rate (anti-HAV IgG \>= 1.0 S/CO) before and after an additional dose of I-HAV vaccine.
Incidence of adverse events following I-HAV vaccination
时间窗: immediate and until 4 weeks after an additional 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.
次要结局
- Geometric mean concentration (GMC) of anti-HAV IgG level(at baseline (1 year after L-HAV vaccination) and 4 weeks after an additional I-HAV vaccination.)
研究者
Tavitiya Sudjaritruk
Associate Professor
Chiang Mai University