Seroprevalence trends of anti-SARS-CoV-2 antibodies and associated risk factors: a population-based study

Stefano Tancredi¹, Arnaud Chiolero^{2

3

4}, Cornelia Wagner², Moa Lina Haller^{4

5}, Patricia Chocano-Bedoya^{2

4}, Natalia Ortega^{2

4}, Nicolas Rodondi^{4

5}, Laurent Kaufmann⁶, Elsa Lorthe⁷, Hélène Baysson^{7

8}, Silvia Stringhini^{7

8

9}, Gisela Michel¹⁰, Chantal Lüdi¹⁰, Erika Harju^{10

11}, Irene Frank¹¹, Medea Imboden^{12

13}, Melissa Witzig^{12

13}, Dirk Keidel^{12

13}, Nicole Probst-Hensch^{12

13}, Rebecca Amati¹⁴, Emiliano Albanese¹⁴, Laurie Corna¹⁵, Luca Crivelli¹⁵, Julia Vincentini¹⁶, Semira Gonseth Nusslé¹⁶, Murielle Bochud¹⁶, Valérie D'Acremont^{12

16}, Philipp Kohler¹⁷, Christian R Kahlert^{17

18}, Alexia Cusini¹⁹, Anja Frei²⁰, Milo A Puhan²⁰, Marco Geigges²⁰, Marco Kaufmann²⁰, Jan Fehr²⁰, Stéphane Cullati^{2

21}; Corona Immunitas Research Group

Collaborators, Affiliations

Collaborators

Corona Immunitas Research Group:
Antonio Amendola, Alexia Anagnostopoulos, Daniela Anker, Anna Maria Annoni, Hélène Aschmann, Andrew Azman, Antoine Bal, Tala Ballouz, Kleona Bezani, Annette Blattmann, Patrick Bleich, Patrick Bodenmann, Peter Buttaroni, Audrey Butty, Anne Linda Camerini, Patricia Orializ Chocano-Bedoya, Prune Collombet, Diana Sofia Da Costa Santos, Agathe Deschamps, Paola D'Ippolito, Anja Domenghino, Richard Dubos, Roxane Dumont, Olivier Duperrex, Julien Dupraz, Malik Egger, Emna El-May, Nacira El Merjani, Nathalie Engler, Adina Mihaela Epure, Lukas Erksam, Sandrine Estoppey, Marta Fadda, Vincent Faivre, Andrea Felappi, Maddalena Fiordelli, Antoine Flahault, Luc Fornerod, Cristina Fragoso Corti, Natalie Francioli, Marion Frangville, Irène Frank, Giovanni Franscella, Clément Graindorge, Idris Guessous, Séverine Harnal, Emilie Jendly, Ayoung Jeong, Laurent Kaiser, Simone Kessler, Christine Krähenbühl, Susi Kriemler, Julien Lamour, Sara Levati, Pierre Lescuyer, Andrea Loizeau, Chantal Luedi, Jean-Luc Magnin, Chantal Martinez, Eric Masserey, Dominik Menges, Rosalba Morese, Nicolai Mösli, Natacha Noël, Daniel Henry Paris, Jérôme Pasquier, Francesco Pennacchio, Stefan Pfister, Giovanni Piumatti, Géraldine Poulain, Caroline Pugin, Milo Puhan, Nick Pullen, Thomas Radtke, Manuela Rasi, Aude Richard, Viviane Richard, Claude-François Robert, Pierre-Yves Rodondi, Serena Sabatini, Khadija Samir, Javier Sanchis Zozaya, Virginie Schlüter, Alexia Schmid, Valentine Schneider, Maria Schüpbach, Nathalie Schwab, Claire Semaani, Alexandre Speierer, Amélie Steiner-Dubuis, Stéphanie Testini, Julien Thabard, Mauro Tonolla, Nicolas Troillet, Agne Ulyte, Sophie Vassaux, Thomas Vermes, Jennifer Villers, Viktor von Wyl, Rylana Wenger, Erin West, Ania Wisniak, María-Eugenia Zaballa, Kyra Zens, Claire Zuppinger

Affiliations

¹ Population Health Laboratory (#PopHealthLab), University of Fribourg, Route Des Arsenaux 41, 1700, Fribourg, Switzerland. stefano.tancredi@unifr.ch.
² Population Health Laboratory (#PopHealthLab), University of Fribourg, Route Des Arsenaux 41, 1700, Fribourg, Switzerland.
³ School of Population and Global Health, McGill University, Montreal, Canada.
⁴ Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland.
⁵ Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
⁶ Cantonal Public Health Service of the Canton of Neuchâtel, Neuchâtel, Switzerland.
⁷ Unit of Population Epidemiology, Division of Primary Care Medicine, Geneva University Hospitals, Geneva, Switzerland.
⁸ Department of Health and Community Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
⁹ University Center for General Medicine and Public Health, University of Lausanne, Lausanne, Switzerland.
¹⁰ Department Health Sciences and Medicine, University of Lucerne, Lucerne, Switzerland.
¹¹ Clinical Trial Unit, Lucerne Cantonal Hospital, Lucerne, Switzerland.
¹² Swiss Tropical and Public Health Institute, Allschwil, Switzerland.
¹³ University of Basel, Basel, Switzerland.
¹⁴ Institute of Public Health, Faculty of Biomedical Sciences, Università Della Svizzera Italiana, Lugano, Switzerland.
¹⁵ Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Manno, Switzerland.
¹⁶ Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland.
¹⁷ Division of Infectious Diseases and Hospital Epidemiology, Cantonal Hospital St Gallen, St Gallen, Switzerland.
¹⁸ Department of Infectious Diseases and Hospital Epidemiology, Children's Hospital of Eastern Switzerland, St. Gallen, Switzerland.
¹⁹ Division of Infectious Diseases, Cantonal Hospital of Grisons, Chur, Switzerland.
²⁰ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland.
²¹ Department of Readaptation and Geriatrics, University of Geneva, Geneva, Switzerland.

PMID: 36870034
PMCID: PMC9985433
DOI: 10.1007/s15010-023-02011-0

Seroprevalence trends of anti-SARS-CoV-2 antibodies and associated risk factors: a population-based study

Stefano Tancredi et al. Infection. 2023 Oct.

. 2023 Oct;51(5):1453-1465.

doi: 10.1007/s15010-023-02011-0. Epub 2023 Mar 4.

Authors

Collaborators

Corona Immunitas Research Group:
Antonio Amendola, Alexia Anagnostopoulos, Daniela Anker, Anna Maria Annoni, Hélène Aschmann, Andrew Azman, Antoine Bal, Tala Ballouz, Kleona Bezani, Annette Blattmann, Patrick Bleich, Patrick Bodenmann, Peter Buttaroni, Audrey Butty, Anne Linda Camerini, Patricia Orializ Chocano-Bedoya, Prune Collombet, Diana Sofia Da Costa Santos, Agathe Deschamps, Paola D'Ippolito, Anja Domenghino, Richard Dubos, Roxane Dumont, Olivier Duperrex, Julien Dupraz, Malik Egger, Emna El-May, Nacira El Merjani, Nathalie Engler, Adina Mihaela Epure, Lukas Erksam, Sandrine Estoppey, Marta Fadda, Vincent Faivre, Andrea Felappi, Maddalena Fiordelli, Antoine Flahault, Luc Fornerod, Cristina Fragoso Corti, Natalie Francioli, Marion Frangville, Irène Frank, Giovanni Franscella, Clément Graindorge, Idris Guessous, Séverine Harnal, Emilie Jendly, Ayoung Jeong, Laurent Kaiser, Simone Kessler, Christine Krähenbühl, Susi Kriemler, Julien Lamour, Sara Levati, Pierre Lescuyer, Andrea Loizeau, Chantal Luedi, Jean-Luc Magnin, Chantal Martinez, Eric Masserey, Dominik Menges, Rosalba Morese, Nicolai Mösli, Natacha Noël, Daniel Henry Paris, Jérôme Pasquier, Francesco Pennacchio, Stefan Pfister, Giovanni Piumatti, Géraldine Poulain, Caroline Pugin, Milo Puhan, Nick Pullen, Thomas Radtke, Manuela Rasi, Aude Richard, Viviane Richard, Claude-François Robert, Pierre-Yves Rodondi, Serena Sabatini, Khadija Samir, Javier Sanchis Zozaya, Virginie Schlüter, Alexia Schmid, Valentine Schneider, Maria Schüpbach, Nathalie Schwab, Claire Semaani, Alexandre Speierer, Amélie Steiner-Dubuis, Stéphanie Testini, Julien Thabard, Mauro Tonolla, Nicolas Troillet, Agne Ulyte, Sophie Vassaux, Thomas Vermes, Jennifer Villers, Viktor von Wyl, Rylana Wenger, Erin West, Ania Wisniak, María-Eugenia Zaballa, Kyra Zens, Claire Zuppinger

Affiliations

¹ Population Health Laboratory (#PopHealthLab), University of Fribourg, Route Des Arsenaux 41, 1700, Fribourg, Switzerland. stefano.tancredi@unifr.ch.
² Population Health Laboratory (#PopHealthLab), University of Fribourg, Route Des Arsenaux 41, 1700, Fribourg, Switzerland.
³ School of Population and Global Health, McGill University, Montreal, Canada.
⁴ Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland.
⁵ Department of General Internal Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
⁶ Cantonal Public Health Service of the Canton of Neuchâtel, Neuchâtel, Switzerland.
⁷ Unit of Population Epidemiology, Division of Primary Care Medicine, Geneva University Hospitals, Geneva, Switzerland.
⁸ Department of Health and Community Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
⁹ University Center for General Medicine and Public Health, University of Lausanne, Lausanne, Switzerland.
¹⁰ Department Health Sciences and Medicine, University of Lucerne, Lucerne, Switzerland.
¹¹ Clinical Trial Unit, Lucerne Cantonal Hospital, Lucerne, Switzerland.
¹² Swiss Tropical and Public Health Institute, Allschwil, Switzerland.
¹³ University of Basel, Basel, Switzerland.
¹⁴ Institute of Public Health, Faculty of Biomedical Sciences, Università Della Svizzera Italiana, Lugano, Switzerland.
¹⁵ Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Manno, Switzerland.
¹⁶ Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland.
¹⁷ Division of Infectious Diseases and Hospital Epidemiology, Cantonal Hospital St Gallen, St Gallen, Switzerland.
¹⁸ Department of Infectious Diseases and Hospital Epidemiology, Children's Hospital of Eastern Switzerland, St. Gallen, Switzerland.
¹⁹ Division of Infectious Diseases, Cantonal Hospital of Grisons, Chur, Switzerland.
²⁰ Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland.
²¹ Department of Readaptation and Geriatrics, University of Geneva, Geneva, Switzerland.

PMID: 36870034
PMCID: PMC9985433
DOI: 10.1007/s15010-023-02011-0

Abstract

Purpose: We aimed to assess the seroprevalence trends of SARS-CoV-2 antibodies in several Swiss cantons between May 2020 and September 2021 and investigate risk factors for seropositivity and their changes over time.

Methods: We conducted repeated population-based serological studies in different Swiss regions using a common methodology. We defined three study periods: May-October 2020 (period 1, prior to vaccination), November 2020-mid-May 2021 (period 2, first months of the vaccination campaign), and mid-May-September 2021 (period 3, a large share of the population vaccinated). We measured anti-spike IgG. Participants provided information on sociodemographic and socioeconomic characteristics, health status, and adherence to preventive measures. We estimated seroprevalence with a Bayesian logistic regression model and the association between risk factors and seropositivity with Poisson models.

Results: We included 13,291 participants aged 20 and older from 11 Swiss cantons. Seroprevalence was 3.7% (95% CI 2.1-4.9) in period 1, 16.2% (95% CI 14.4-17.5) in period 2, and 72.0% (95% CI 70.3-73.8) in period 3, with regional variations. In period 1, younger age (20-64) was the only factor associated with higher seropositivity. In period 3, being aged ≥ 65 years, with a high income, retired, overweight or obese or with other comorbidities, was associated with higher seropositivity. These associations disappeared after adjusting for vaccination status. Seropositivity was lower in participants with lower adherence to preventive measures, due to a lower vaccination uptake.

Conclusions: Seroprevalence sharply increased over time, also thanks to vaccination, with some regional variations. After the vaccination campaign, no differences between subgroups were observed.

Keywords: COVID-19 pandemic; Epidemiology; Public health; SARS-CoV-2; Seroprevalence; Surveillance.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

**Fig. 1**
Blood samplings per week and daily confirmed COVID-19 cases reported in Switzerland, May 2020–September 2021

**Fig. 2**
Trends of seroprevalence estimates (IgG anti SARS-CoV-2 Spike) per canton and by age group, Corona Immunitas study, Switzerland, May 2020–September 2021

See this image and copyright information in PMC

References

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Seroprevalence trends of anti-SARS-CoV-2 antibodies and associated risk factors: a population-based study

Collaborators

Affiliations

Seroprevalence trends of anti-SARS-CoV-2 antibodies and associated risk factors: a population-based study

Authors

Collaborators

Affiliations

Abstract

Conflict of interest statement

Figures

References

MeSH terms

Substances