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. 2022 Jan 9;22(1):41.
doi: 10.1186/s12879-021-06973-0.

Prevalence of SARS-Cov-2 antibodies and living conditions: the French national random population-based EPICOV cohort

Josiane Warszawski  1 , Anne-Lise Beaumont  2 , Rémonie Seng  3 , Xavier de Lamballerie  4 , Delphine Rahib  5 , Nathalie Lydié  5 , Rémy Slama  6 , Sylvain Durrleman  7 , Philippe Raynaud  8 , Patrick Sillard  9 , François Beck  5 , Laurence Meyer  2 , Nathalie Bajos  10 ; EPICOV study group
Collaborators, Affiliations

Prevalence of SARS-Cov-2 antibodies and living conditions: the French national random population-based EPICOV cohort

Josiane Warszawski et al. BMC Infect Dis. .

Abstract

Background: We aimed to estimate the seroprevalence of SARS-CoV-2 infection in France and to identify the populations most exposed during the first epidemic wave.

Methods: Random selection of individuals aged 15 years or over, from the national tax register (96% coverage). Socio-economic data, migration history, and living conditions were collected via self-computer-assisted-web or computer-assisted-telephone interviews. Home self-sampling was performed for a random subsample, to detect IgG antibodies against spike protein (Euroimmun), and neutralizing antibodies with in-house assays, in dried blood spots (DBS).

Results: The questionnaire was completed by 134,391 participants from May 2nd to June 2st, 2020, including 17,441 eligible for DBS 12,114 of whom were tested. ELISA-S seroprevalence was 4.5% [95% CI 3.9-5.0] overall, reaching up to 10% in the two most affected areas. High-density residences, larger household size, having reported a suspected COVID-19 case in the household, working in healthcare, being of intermediate age and non-daily tobacco smoking were independently associated with seropositivity, whereas living with children or adolescents did not remain associated after adjustment for household size. Adjustment for both residential density and household size accounted for much of the higher seroprevalence in immigrants born outside Europe, twice that in French natives in univariate analysis.

Conclusion: The EPICOV cohort is one of the largest national representative population-based seroprevalence surveys for COVID-19. It shows the major role of contextual living conditions in the initial spread of COVID-19 in France, during which the availability of masks and virological tests was limited.

Keywords: COVID-19; Population-based survey; Random sample; Risk factors; SARS-COV-2; Seroprevalence.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Flowchart: the national EpiCov cohort, round 1—May 2020
Fig. 2
Fig. 2
Geographic prevalence of antibodies against SARS-CoV-21 in people living in France2 at the end of the first lockdown: the national EpiCov cohort, round 1—May 2020
See this image and copyright information in PMC

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