This Study Will Evaluate the Persistence of Hepatitis A Antibodies, 8 Years and 10 Years Later, in Children Who Had Received Havrix at Selected Health Centres of Panama

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the persistence of hepatitis A antibodies, approximately 8 years and 10 years post vaccination with the complete series of Havrix (2 doses) and the partial series completion (1 dose).

Detailed Description
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The study comprises of two independent cross-sectional surveys (Year 8 and Year 10). The first cross-sectional serosurvey will evaluate the long term persistence of immunity approximately 8 years post vaccine administration and the second cross-sectional study will evaluate long term persistence, approximately 10 years post vaccine administration.

Official Title
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Long Term Hepatitis A Virus (HAV) Antibody Persistence in Children Vaccinated With 1 Dose and Those Vaccinated With 2 Doses of Havrix in Panama

Conditions
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Hepatitis A Vaccine

Intervention / Treatment
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* Other: Blood sample collection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects whose parent(s)/ LAR(s), in the opinion of the investigator, can and will comply with the requirements of the protocol. Written informed assent/consent obtained from the subject or subject's parent(s)/ LAR(s) of the subject. Available HAV vaccination records. Children who have received either 1 or two doses of Havrix at selected health centres of Panama. Children with ≥ 7 years and < 10 years between last dose and Persistence Visit 1 (Year 8) and children ≥ 10 years and < 13 years between last dose and Persistence Visit 1' (Year 10). Exclusion Criteria: Child in care. Subjects with history of vaccination with other hepatitis A vaccines other than Havrix. Subjects with known past history of hepatitis A infection, both without vaccination and after they received the last dose of Havrix (1 dose or the complete 2 dose schedule).

Ages Eligible for Study
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Minimum Age: 8 Years
Maximum Age: 15 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Havrix 1 dose_Year 8 Group<br>Subjects who received one dose of Havrix vaccine and with more than or equal to (≥) 7 years and less than (<) 10 years between the administration of the vaccine dose and the Persistence Visit at Year 8 and who participated in the Year 8 cross-sectional survey. | Other: Blood sample collection<br>* A blood sample ( 5mL) will be collected from all subjects at each cross-sectional survey (Year 8 and Year 10).<br>|
| Other: Havrix 2 doses_Year 8 Group<br>Subjects who received two doses of Havrix vaccine and with more than or equal to (≥) 7 years and less than (<) 10 years between the administration of the last vaccine dose and the Persistence Visit at Year 8 and who participated in the Year 8 cross-sectional survey. | Other: Blood sample collection<br>* A blood sample ( 5mL) will be collected from all subjects at each cross-sectional survey (Year 8 and Year 10).<br>|
| Other: Havrix 1 dose_Year 10 Group<br>Subjects who received one dose of Havrix vaccine and with more than or equal to (≥) 10 years and less than (<) 13 years between the administration of the vaccine dose and the Persistence Visit at Year 10 and who participated in the Year 10 cross-sectional survey. | Other: Blood sample collection<br>* A blood sample ( 5mL) will be collected from all subjects at each cross-sectional survey (Year 8 and Year 10).<br>|
| Other: Havrix 2 doses_Year 10 Group<br>Subjects who received two doses of Havrix vaccine and with more than or equal to (≥) 10 years and less than (<) 13 years between the administration of the vaccine dose and the Persistence Visit at Year 10 and who participated in the Year 10 cross-sectional survey. | Other: Blood sample collection<br>* A blood sample ( 5mL) will be collected from all subjects at each cross-sectional survey (Year 8 and Year 10).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Subjects With Anti-hepatitis A Virus (HAV) Seropositivity Status at Approximately 8 Years Following Last Administered Havrix Dose | Subjects are defined as being seropositive if their anti-HAV antibody concentration is equal to or above (≥) 15 milli-international unit/milliliter (mIU/mL). | At approximately 8 years after the last administered vaccine dose | 
| Number of Subjects With Anti-HAV Seropositivity Status at Approximately 10 Years Following Last Administered Havrix Dose | Subjects are defined as being seropositive if their anti-HAV antibody concentration is equal to or above (≥) 15 mIU/mL. | At approximately 10 years after the last administered vaccine dose | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Anti-HAV Antibody Concentrations at Approximately 8 Years Following Last Administered Havrix Dose | Anti-HAV antibody concentrations were measured by ELISA, expressed as GMCs, in mIU/mL. The cut-off of the assay was an anti-HAV antibody concentration equal to or above (≥) 15 mIU/mL. | At approximately 8 years after the last administered vaccine dose | 
| Anti-HAV Antibody Concentrations at Approximately 10 Years Following Last Administered Havrix Dose | Anti-HAV antibody concentrations were measured by ELISA, expressed as GMCs, in mIU/mL. The cut-off of the assay was an anti-HAV antibody concentration equal to or above (≥) 15 mIU/mL. | At approximately 10 years after the last administered vaccine dose | 
| Number of Subjects With Anti-HAV Antibody Concentration ≥ 15 mIU/mL at Approximately 8 Years Following Last Administered Havrix Dose - Exploration of Non-inferiority of the 1-dose Schedule Compared to the 2-dose Schedule of Havrix | Subjects are defined as being seropositive if their anti-HAV antibody concentration is equal to or above (≥) 15 mIU/mL. | At approximately 8 years after the last administered vaccine dose | 
| Number of Subjects With Anti-HAV Antibody Concentrations ≥ 15 mIU/mL at Approximately 10 Years Following Last Administered Havrix Dose - Exploration of Non-inferiority of the 1-dose Schedule Compared to the 2-dose Schedule of Havrix | Subjects are defined as being seropositive if their anti-HAV antibody concentration is equal to or above (≥) 15 mIU/mL. | At approximately 10 years after the last administered vaccine dose | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Havrix, Cross-sectional seroprevalence survey, Panama, Long-term persistence, Hepatitis