The investigators performed in April 2020, a screening campaign of asymptomatic staff working in elderly nursing homes in Paris France (EHPAD), where the virus had been circulating actively in March and April 2020. Among 241 employees tested in four nursing homes, 32 (13.2%) were asymptomatic carriers of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-Cov-2). Few data are available concerning the humoral immune response of asymptomatic carriers, the elicitation and duration of neutralizing antibodies and the duration of protection. The purpose of the study is to determine whether these asymptomatic persons develop a humoral immune response, whether this immune response is durable and whether it is protective against the risk of reinfection
The investigators performed in April 2020, a screening campaign of asymptomatic staff working in elderly nursing homes in Paris, France, where the virus had been circulating actively in March and April 2020. Among 241 employees tested in four nursing homes, 32 (13.2%) were asymptomatic carriers of SARS-Cov-2. Few data are available concerning the humoral immune response of asymptomatic carriers, the elicitation and duration of neutralizing antibodies and the duration of protection. The main objective of this study is to describe the SARS-Cov-2 asymptomatic employees with positive immunoglobulin G (igG) serology at month 1-2 post infection. Secondary objectives are * To describe the proportion of asymptomatic persons with SARS-Cov-2 antibodies month 3 and 6 post infection * To compare the proportion of persons with SARS-Cov-2 antibodies between asymptomatic and asymptomatic carriers at M1-2 post infection, M3 and M6 post infection * To determine the factors associated with the appearance of antibodies ( viral load, age, sex, previous history, habitus..) * To study the neutralizing capacities and immune-profiling of SARS-Cov-2 antibodies in vitro * To evaluate the occurrence of Coronavirus Disease 2019 (COVID-19) reinfections in asymptomatic carriers during the second wave. The design will be a case control study between * Cases: SARS-Cov-2 asymptomatic nursing homes employees * Controls: cohort of patients with a symptomatic COVID-19, preferably recruited in nursing homes or in case of difficulties in the virology service of COCHIN Hospital.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SCREENING
Masking
NONE
serology at M3 and serology at M6
HOTEL DIEU Hospital
Paris, France
rate of positive IgG serology
positive IgG (Immunoglobulin G) SARS-Cov-2 serology after infection of asymptomatic employees
Time frame: month 1-2 post infection
rate of positive IgG serology
positive IgG (Immunoglobulin G) SARS-Cov-2 serology after infection of asymptomatic employees
Time frame: month 3-6 post infection
rate of positive immunoglobulin M (IgM) serology
positive IgM SARS-Cov-2 serology after infection of asymptomatic employees
Time frame: month 1-2-3 and 6 post infection
rate of neutralizing antibodies
concentration of neutralizing antibodies
Time frame: month 1-2-3 and 6 post infection
questionnaire
Associated factors with the presence of antibodies
Time frame: month 1-2-3 and 6 post infection
re infection
of asymptomatic patients with SARS-Cov-2
Time frame: through study completion, an average of 8 months
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