Investigation of Immune Amnesia Following Measles Infection in Select African Regions

Study Overview
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Brief Summary
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The goal of this observational study is to investigate the effects of measles virus (MeV) infection on pre-existing immunity, vaccine response, and susceptibility to subsequent illness in children aged 1-15 either with or without acute MeV infection.

Detailed Description
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This is a prospective, observational, longitudinal study to be conducted in West Africa. Eligible children will be enrolled into 1 of 2 arms: acute MeV infection (cases) or no acute MeV infection (controls) as assessed using upper respiratory specimens and blood samples. Blood samples will be collected at screening/enrollment (Day 0) and follow-up visits on Day 14, Week 13, and Week 52, and tested for humoral and cellular immune responses to endemic pathogens to determine changes in antibody diversity and antibody secreting cells (ASCs). All children in each arm will receive rabies vaccination (standard 3-dose series given as pre-exposure prophylaxis [PrEP]), with the first dose randomized to either Week 8 or Week 47 after enrollment. Biological samples will be collected after vaccination to assess if the immune stimulus (rabies vaccine) response differs: 1) between children with and without MeV infection, and 2) based on the timing of the receipt of the rabies vaccine.

Official Title
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Investigation of Immune Amnesia Following Measles Infection in Select African Regions

Conditions
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Measles Infection

Intervention / Treatment
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* Biological: Verorab


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged 1 to 15 years. Ability of the participant's legal or culturally acceptable representative to provide informed consent. Ability to give assent, as appropriate. Stated willingness of parent/guardian and participant as appropriate, to comply with all study procedures. Willingness to receive rabies vaccine. Meet the criteria for assignment to Group 1 or Group 2, as follows: Group 1, cases (acute MeV infection): Clinical signs and symptoms suggestive of acute MeV infection (Koplik spots or skin rash) AND Laboratory confirmed measles: Upper respiratory specimen (swab) PCR for measles positive, OR Serum IgM for measles positive. Group 2, controls (no acute MeV infection): No clinical signs and symptoms suggestive of acute MeV infection (Koplik spots or skin rash) AND Upper respiratory specimen (swab) PCR negative for MeV AND Serum measles IgM negative AND Serum measles IgG positive and previously vaccinated for measles (2nd dose will be offered if appropriate). If serum measles IgG is negative, participant must be willing to be vaccinated regardless of prior measles vaccine history to meet this criterion. Exclusion Criteria: HIV infection or any other immunosuppressive condition or medications. Pregnant or lactating. History of prior measles or immunologic evidence of prior measles in the absence of prior measles vaccination. Severe anemia, defined as hemoglobin less than 8 g/dL. Any acute or chronic condition which, in the opinion of the investigator, constitutes a contraindication to participation in this study.

Ages Eligible for Study
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Minimum Age: 1 Year
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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Group 1 - Actue MeV Infection<br>Participants have acute MeV infection. | Biological: Verorab<br>* Participants in each group will receive rabies vaccination (standard 3-dose series given as PrEP), with the first dose randomized to either Week 8 or Week 47 after enrollment.<br>|
| Group 2 - No Actue MeV Infection<br>Participants do not have acute MeV infection. | Biological: Verorab<br>* Participants in each group will receive rabies vaccination (standard 3-dose series given as PrEP), with the first dose randomized to either Week 8 or Week 47 after enrollment.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in pre-existing immunity | Mean change in a panel of antibody levels over 13 weeks as measured by multiplex serological methods and targeted ELISAs for confirmation. | Week 13 after baseline | 
| Effect of MeV infection on immune response to a controlled immune stimulus (rabies vaccination) | Proportion of subjects with rabies virus neutralizing antibodies (RVNA) titer ≥ 0.5 IU/mL as measured by rapid fluorescent focus inhibition test | 14 days after last PrEP regimen vaccination | 
| Effect of MeV infection on immune response to a controlled immune stimulus | Proportion of subjects with an RVNA titer ≥ lower limit of quantification | 5-6 weeks after the first rabies vaccine dose | 
| Effect of MeV infection on immune response to a controlled immune stimulus | Geometric mean RVNA titer | 5-6 weeks after the first rabies vaccine dose | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in healthcare system encounters | Mean number of non-study sick visit healthcare system encounters during the 1-year follow-up. | 1 year following enrollment | 
| Change in pre-existing immunity | Mean change in a panel of antibody levels over 52 weeks as measured by multiplex serological methods and targeted ELISAs for confirmation. | Week 52 after baseline |