Level of Immunity, Neutralization of the COVID-19 Virus and Reinfections in Residents of 2 Migrant Workers' Residences

Study Overview
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Brief Summary
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A previous seroprevalence survey showed very high seroprevalence levels among residents of the two among the residents of the two migrant workers' hostels surveyed, indicating a high level of circulation of the virus SARS-COV-2 during the 1st wave of COVID-19. The constitution of a cohort after the event would be an opportunity to obtain opportunity to obtain answers to crucial questions: duration of immunity, potential reinfections potential reinfections, potential re-clustering. Going back to check the serological status seems feasible, especiallyespecially in the Foyers de Travailleurs Migrants (high probability of finding the participants). There is an obvious scientific interest around the duration of immunity and reinfections in a population highly exposed during the first wave. Several articles document the decline of IgG antibodies in the months following an infection, but very few infection, but very few evaluate the protective character in the medium term (>=6 months), especially in asymptomatic individuals. We are also concerned about the circulation of We are also concerned about the circulation of new variants and the immunity acquired after infection in residents. To date, no study on the duration of immunity has been conducted in migrant worker's residences.

Official Title
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Determination of the Level of Immunity, Neutralization of the SARS-COV-2 Virus and Reinfections in Residents of 2 Migrant Workers' Residences 10 Months Apart

Conditions
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SARS-COV-2

Intervention / Treatment
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* Biological: Blood and Saliva collection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All individuals who consented to participate in the 1st study and who consent to participate in this study All individuals 18 years of age or older not residing in the 2 MWRs in July 2020 and permanently living in the MWR since September 2020 who consent to participate in this study Exclusion Criteria: Unwillingness to provide informed consent Unwillingness to provide blood Contraindication to venepuncture

Ages Eligible for Study
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Minimum Age: 18 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 |
| --- | --- |
| migrant worker residents<br>The target population will be the 124 residents in the 2 migrant worker residences who were included in the previous seroprevalence study and those who arrived at the 2 residences since September 1st, 2020 | Biological: Blood and Saliva collection<br>* Serological, viral RNA and antigenic test<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Level and quality of current humoral immune protection in the residents of the two migrant workers' residences | To assess the level and quality of current humoral immune protection in the residents of the two migrant workers' residences in Villemomble and Montreuil who were included in the 1st seroprevalence study in July 2020, approximately 10 months later (May 2021) | 15 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Immunity and protection | Identify potential reinfections (reported symptoms confirmed by positive PCR tests) or resurgence of symptoms (long COVID) among residents who were seropositive in July 2020 Assess the evolution of antibodies (IgA, IgM, IgG) approximately 10 months after the first test in Sars-CoV-2 seropositive individuals in July To evaluate the neutralizing and therefore protective activity of the re-measured antibodies, and their level of affinity maturation to SARS-COV-2 as well as their efficacy against the mainly circulating variants: B.1.1.7 (UK), B.1.351 (South Africa) and P.1 (Brazil) | 15 days | 
| New infections and screening | Estimate the proportion of infections (reported symptoms and/or positive PCR tests)/exposure to the virus in people newly arrived since September 2020 In case of SARS-COV-2 RNA detection, characterize the virus subtype (genomic sequencing) Document the turnover in MWR populations to guide MSF activities in the future | 15 days | 
| COVID Vaccination | Assess the proportion of participants already vaccinated or interested in the future COVID vaccination campaign and document the reasons for those who express doubts or plan to refuse vaccination To evaluate the performance of the LuLISA technique for the response to SARS-CoV-2 N and S proteins To evaluate the performance of a rapid serological test on strip, LuLISA Stripe developed by the Institute Pasteur by comparison to the LuLISA technique To evaluate the performance of a rapid N and S antigenic test on saliva, LuLISA Flash, developed by the Institut Pasteur, by comparing it to the RT-PCR method To evaluate the performance of an alternative antigenic test on saliva with very high sensitivity, LuLISA Stick, developed by Institute Pasteur, by comparing it to the RT-PCR method Evaluate the performance of a rapid molecular RT-LAMP test developed by Institute Pasteur (depending on availability) by comparing it to the RT-PCR method | 15 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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COVID-19, migrant workers' residences, Immunity, protection