Immune Responses and Immunological Tolerance After Rabies Booster Vaccination in HIV-infected Adults

Study Overview
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Brief Summary
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To study the humoral and cell-mediated immune responses in HIV-infected adults who had previously received rabies booster vaccination more than a year before

Detailed Description
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Previous study has shown the higher immunogenicity response among HIV-infected adults who received a single visit 4-site intradermal rabies booster vaccination than those who received the conventional intramuscular regimen. The investigators follow the persistence of these effects. Also, the regulatory T cell levels were examined after the rabies booster vaccination .

Official Title
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Humoral and Cell-mediated Immune Responses and Immunological Tolerance After Rabies Booster Vaccination in Previously Rabies Immunized HIV-infected Adults

Conditions
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Rabies

Intervention / Treatment
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* Procedure: Blood drawn after rabies booster vaccination


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy HIV-infected adults Previously received rabies booster vaccination by participation in the previous clinical trials of the investigators. Exclusion Criteria: Have any active opportunistic infections Received blood or blood product within 3 months Received anti-malarial drugs Received rabies vaccination in a previous year.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The volunteers who participated in the previous clinical trials were invited to join this study. Of which, there were 2 groups, one received a single visit 4-site intradermal rabies booster vaccination. The another received a conventional intramuscular rabies booster vaccination on day 0 and 3.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: single visit 4-site ID vaccination<br>Blood would be drawn from those who received a single visit 4-site ID rabies booster vaccination in the previous trial. | Procedure: Blood drawn after rabies booster vaccination<br>* Blood would be drawn for testing of rabies neutralizing antibody titers, rabies specific T lymphocytes and regulatory T cells after receipt of rabies booster vaccination at least a year before.<br>|
| Active Comparator: Conventional IM vaccination<br>Blood would be drawn from those who received a conventional intramuscular rabies booster vaccination in the previous trial. | Procedure: Blood drawn after rabies booster vaccination<br>* Blood would be drawn for testing of rabies neutralizing antibody titers, rabies specific T lymphocytes and regulatory T cells after receipt of rabies booster vaccination at least a year before.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rabies Neutralizing Antibody Titers (RNab) | Rabies Neutralizing Antibody Titers would be represented and compared by geometric mean titers (GMTs) | GMTs of RNab and proportion of volunteers who have had RNab above protective antibody levels (0.5 IU/ml) after receipt of rabies booster vaccination at least a year before were compared between 2 arms at one time point on the date of study recruitment. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rabies specific T cell response | Rabies specific T cell response is measured by Enzyme - linked Immunospot Assay (ELISPOT) | Numbers of spots, of which represent the rabies specific T cell response after receipt of rabies booster vaccination at least a year before were compared between 2 arms at one time point on the date of study recruitment. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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rabies vaccination