Prevalence of SARS-CoV-2 antibodies in France: results from nationwide serological surveillance

Stéphane Le Vu (1) , Gabrielle Jones (1) , François Anna (2, 3) , Thierry Rose (4) , Jean-Baptiste Richard (1) , Sibylle Bernard-Stoecklin (1) , Sophie Goyard (4) , Caroline Demeret (5) , Olivier Helynck (6) , Corinne Robin (7) , Virgile Monnet (8) , Louise Perrin De Facci (9) , Marie-Noelle Ungeheuer (9) , Lucie Léon (1) , Yvonnick Guillois (1) , Laurent Filleul (1) , Pierre Charneau (2, 3) , Daniel Lévy-Bruhl (1) , Sylvie van Der Werf (5, 10) , Harold Noel (1)

1 Santé publique France - French National Public Health Agency [Saint-Maurice, France]
2 Virologie Moléculaire et Vaccinologie / Molecular Virology and Vaccinology
3 Laboratoire commun Pasteur-TheraVectys
4 Biologie Cellulaire des Lymphocytes - Lymphocyte Cell Biology
5 GMV-ARN (UMR_3569 / U-Pasteur_2) - Génétique Moléculaire des Virus à ARN - Molecular Genetics of RNA Viruses
6 Chimie et Biocatalyse
7 Laboratoire CERBA [Saint Ouen l'Aumône]
8 BSL - Biomnis Sample Library
9 ICAReB - Investigation Clinique et d’Accès aux Ressources Biologiques (Plate-forme) - Clinical Investigation and Access to BioResources
10 CNR - laboratoire coordonnateur - Centre National de Référence des virus des infections respiratoires (dont la grippe) - National Reference Center Virus Influenzae [Paris]

Background Assessment of cumulative incidence of SARS-CoV-2 infections is critical for monitoring the course and the extent of the epidemic. As asymptomatic or mild cases were typically not captured by surveillance data in France, we implemented nationwide serological surveillance. We present estimates for prevalence of anti-SARS-CoV-2 antibodies in the French population and the proportion of infected individuals who developed potentially protective neutralizing antibodies throughout the first epidemic wave. Methods We performed serial cross-sectional sampling of residual sera over three periods: prior to (9- 15 March), during (6-12 April) and following (11-17 May) a nationwide lockdown. Each sample was tested for anti-SARS-CoV-2 IgG antibodies targeting the Nucleoprotein and Spike using two Luciferase-Linked ImmunoSorbent Assays, and for neutralising antibodies using a pseudo-neutralisation assay. We fitted a general linear mixed model of seropositivity in a Bayesian framework to derive prevalence estimates stratified by age, sex and region. Findings In total, sera from 11 021 individuals were analysed. Nationwide seroprevalence of SARS-CoV-2 antibodies was estimated at 0.41% [0.05−0.88] mid-March, 4.14% [3.31−4.99] mid-April and 4.93% [4.02−5.89] mid-May. Approximately 70% of seropositive individuals had detectable neutralising antibodies. Seroprevalence was higher in regions where circulation occurred earlier and was more intense. Seroprevalence was lowest in children under 10 years of age (2.72% [1.10−4.87]). Interpretation Seroprevalence estimates confirm that the nationwide lockdown substantially curbed transmission and that the vast majority of the French population remains susceptible to SARS-CoV-2. Low seroprevalence in school age children suggests limited susceptibility and/or transmissibility in this age group. Our results show a clear picture of the progression of the first epidemic wave and provide a framework to inform the ongoing public health response as viral transmission is picking up again in France and globally.

Domains: Life Sciences [q-bio]; Santé publique et épidémiologie

Stéphane Le Vu, Gabrielle Jones, François Anna, Thierry Rose, Jean-Baptiste Richard, et al.. Prevalence of SARS-CoV-2 antibodies in France: results from nationwide serological surveillance. Nature Communications, 2021, ⟨10.1101/2020.10.20.20213116⟩. ⟨pasteur-03147098v2⟩