International Journal of Public Health (Feb 2022)

The Corona Immunitas Digital Follow-Up eCohort to Monitor Impacts of the SARS-CoV-2 Pandemic in Switzerland: Study Protocol and First Results

  • Alexandre Speierer,
  • Alexandre Speierer,
  • Patricia O. Chocano-Bedoya,
  • Patricia O. Chocano-Bedoya,
  • Daniela Anker,
  • Alexia Schmid,
  • Dirk Keidel,
  • Dirk Keidel,
  • Thomas Vermes,
  • Thomas Vermes,
  • Medea Imboden,
  • Medea Imboden,
  • Sara Levati,
  • Giovanni Franscella,
  • Laurie Corna,
  • Rebecca Amati,
  • Erika Harju,
  • Chantal Luedi,
  • Gisela Michel,
  • Caroline Veys-Takeuchi,
  • Claire Zuppinger,
  • Semira Gonseth Nusslé,
  • Valérie D’Acremont,
  • Ismaël Tall,
  • Éric Salberg,
  • Hélène Baysson,
  • Hélène Baysson,
  • Elsa Lorthe,
  • Francesco Pennacchio,
  • Anja Frei,
  • Marco Kaufmann,
  • Marco Geigges,
  • Erin Ashley West,
  • Nathalie Schwab,
  • Nathalie Schwab,
  • Stéphane Cullati,
  • Stéphane Cullati,
  • Arnaud Chiolero,
  • Arnaud Chiolero,
  • Christian Kahlert,
  • Christian Kahlert,
  • Silvia Stringhini,
  • Silvia Stringhini,
  • Silvia Stringhini,
  • Fabian Vollrath,
  • Nicole Probst-Hensch,
  • Nicole Probst-Hensch,
  • Nicolas Rodondi,
  • Nicolas Rodondi,
  • Milo A. Puhan,
  • Viktor von Wyl

DOI
https://doi.org/10.3389/ijph.2022.1604506
Journal volume & issue
Vol. 67

Abstract

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Objectives: To describe the rationale, organization, and procedures of the Corona Immunitas Digital Follow-Up (CI-DFU) eCohort and to characterize participants at baseline.Methods: Participants of Corona Immunitas, a population-based nationwide SARS-CoV-2 seroprevalence study in Switzerland, were invited to join the CI-DFU eCohort in 11 study centres. Weekly online questonnaires cover health status changes, prevention measures adherence, and social impacts. Monthly questionnaires cover additional prevention adherence, contact tracing apps use, vaccination and vaccine hesitancy, and socio-economic changes.Results: We report data from the 5 centres that enrolled in the CI-DFU between June and October 2020 (covering Basel City/Land, Fribourg, Neuchâtel, Ticino, Zurich). As of February 2021, 4636 participants were enrolled and 85,693 weekly and 27,817 monthly questionnaires were collected. Design-based oversampling led to overrepresentation of individuals aged 65+ years. People with higher education and income were more likely to enroll and be retained.Conclusion: Broad enrolment and robust retention of participants enables scientifically sound monitoring of pandemic impacts, prevention, and vaccination progress. The CI-DFU eCohort demonstrates proof-of-principle for large-scale, federated eCohort study designs based on jointly agreed principles and transparent governance.

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