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.
Study Type
OBSERVATIONAL
Serological, viral RNA and antigenic test
Foyer de travailleurs migrants
Montreuil, Île-de-France Region, France
Foyer de travailleurs migrants
Villemomble, Île-de-France Region, France
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)
Time frame: 15 days
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)
Time frame: 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
Time frame: 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
Time frame: 15 days
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