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. 2022 May 3;14(5):957.
doi: 10.3390/v14050957.

Seroprevalence of SARS-CoV-2 IgG Antibodies and Factors Associated with SARS-CoV-2 IgG Neutralizing Activity among Primary Health Care Workers 6 Months after Vaccination Rollout in France

Dorine Decarreaux  1   2   3 , Marie Pouquet  2 , Cecile Souty  2 , Ana-Maria Vilcu  2 , Pol Prévot-Monsacre  2 , Toscane Fourié  3 , Paola Mariela Saba Villarroel  3 , Stephane Priet  3 , Hélène Blanché  4 , Jean-Marc Sebaoun  4 , Jean-François Deleuze  4 , Clément Turbelin  2 , Andréas Werner  5 , Fabienne Kochert  5 , Brigitte Grosgogeat  6   7   8   9 , Pascaline Rabiega  10 , Julien Laupie  8 , Nathalie Abraham  10 , Caroline Guerrisi  2 , Harold Noël  11 , Sylvie Van der Werf  12   13 , Fabrice Carrat  2   14 , Thomas Hanslik  2   15   16 , Remi Charrel  3 , Xavier De Lamballerie  3 , Thierry Blanchon  2 , Alessandra Falchi  1
Affiliations

Seroprevalence of SARS-CoV-2 IgG Antibodies and Factors Associated with SARS-CoV-2 IgG Neutralizing Activity among Primary Health Care Workers 6 Months after Vaccination Rollout in France

Dorine Decarreaux et al. Viruses. .

Abstract

We aimed to investigate the immunoglobulin G response and neutralizing activity against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) among primary health care workers (PHCW) in France and assess the association between the neutralizing activity and several factors, including the coronavirus disease 2019 (COVID-19) vaccination scheme. A cross-sectional survey was conducted between 10 May 2021 and 31 August 2021. Participants underwent capillary blood sampling and completed a questionnaire. Sera were tested for the presence of antibodies against the nucleocapsid (N) protein and the S-1 portion of the spike (S) protein and neutralizing antibodies. In total, 1612 PHCW were included. The overall seroprevalences were: 23.6% (95% confidence interval (CI) 21.6-25.7%) for antibodies against the N protein, 94.7% (93.6-95.7%) for antibodies against the S protein, and 81.3% (79.4-83.2%) for neutralizing antibodies. Multivariate regression analyses showed that detection of neutralizing antibodies was significantly more likely in PHCW with previous SARS-CoV-2 infection than in those with no such history among the unvaccinated (odds ratio (OR) 16.57, 95% CI 5.96-59.36) and those vaccinated with one vaccine dose (OR 41.66, 95% CI 16.05-120.78). Among PHCW vaccinated with two vaccine doses, the detection of neutralizing antibodies was not significantly associated with previous SARS-CoV-2 infection (OR 1.31, 95% CI 0.86-2.07), but was more likely in those that received their second vaccine dose within the three months before study entry than in those vaccinated more than three months earlier (OR 5.28, 95% CI 3.51-8.23). This study highlights that previous SARS-CoV-2 infection and the time since vaccination should be considered when planning booster doses and the design of COVID-19 vaccine strategies.

Keywords: SARS-CoV-2 antibodies; health care workers; neutralizing antibodies; primary care; seroprevalence.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Flow chart of the primary healthcare worker (PHCW) participants enrolled from May to August 2021 (COVID-SéroPRIM study, France, 2021).
Figure 2
Figure 2
Antibody levels (BAU/mL) for IgG antibodies against the S protein according to (a) the number of COVID-19 vaccine doses received along with the presence or absence of self-reported SARS-CoV-2 infection among the PHCWs; (b) time since the last vaccination among vaccinees; (c) age (years) of the PHCWs, May 2021 to August 2021 (n = 1602; COVID-SéroPRIM study, France, 2021).
Figure 2
Figure 2
Antibody levels (BAU/mL) for IgG antibodies against the S protein according to (a) the number of COVID-19 vaccine doses received along with the presence or absence of self-reported SARS-CoV-2 infection among the PHCWs; (b) time since the last vaccination among vaccinees; (c) age (years) of the PHCWs, May 2021 to August 2021 (n = 1602; COVID-SéroPRIM study, France, 2021).
Figure 3
Figure 3
Distribution of seroneutralization titers among the PHCWs, May 2021 to August 2021 (N = 1602; COVID-SéroPRIM study, France, 2021).
Figure 4
Figure 4
Boxplot of the quantitative ELISA-S results according to neutralizing antibody titers among the PHCWs (N = 1602; COVID-SéroPRIM study, France, 2021).
See this image and copyright information in PMC

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