We thank the Swiss Federal Statistical Office for providing the randomized list of participants for the main population-based portion of our study. We thank SSPH+ for their help with coordination of all study sites. We lastly wish to thank all nurses, medical students, researchers, clinicians, and staff that contributed to the implementation of Corona Immunitas.

Corona Immunitas Research Group The following are members of Corona Immunitas Research Group (including the authors of the present article), listed in alphabetical order: Emiliano Albanese, MD PhD (Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; emiliano.albanese@usi.ch), Rebecca Amati, PhD (Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; rebecca.amati@usi.ch), Antonio Amendola, Msc (Department of Business Economics, Health & Social Care (DEASS), University of Applied Sciences & Arts of Southern Switzerland (SUPSI), Manno, Switzerland; antonio.amendola@supsi.ch), Daniela Anker, Msc (Population Health Laboratory (#PopHealthLab), University of Fribourg, Fribourg, Switzerland; Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland; daniela.anker@unifr.ch), Anna Maria Annoni, Msc (Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; anna.maria.annoni@usi.ch), Andrew Azman, PhD (Division of Primary Care, Geneva University Hospitals, Geneva, Switzerland; Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Institute of Global Health, University of Geneva, Geneva, Switzerland; andrew.azman@hcuge.ch), Frank Bally, MD (Institut central des hôpitaux, Hôpital du Valais, Sion, Switzerland ; frank.bally@hopitalvs.ch), Bettina Balmer, MD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; balmer.schiltknecht@gmail.com), Hélène Baysson, PhD (Department of Health and Community Medicine, University of Geneva, Geneva, Switzerland; helene.baysson@unige.ch), Delphine Berthod, MD (Institut central des hôpitaux, Hôpital du Valais, Sion, Switzerland ; delphine.berthod@hopitalvs.ch), Jacob Blankenberger, BSc (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; jacob.blankenberger@uzh.ch), Murielle Bochud, MD PhD (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland, murielle.bochud@unisante.ch), Patrick Bodenmann, MD Msc (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; patrick.bodenmann@unisante.ch), Matthias Bopp, Dr. phil.II PhD MPH (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; matthias.bopp@uzh.ch), Audrey Butty, MD (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; audrey.butty@unisante.ch), Anne Linda Camerini, PhD (Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; anne.linda.camerini@usi.ch), Céline Cappeli, BSc (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; celine.capelli@uzh.ch), Cristian Carmelli, PhD (Population Health Laboratory (#PopHealthLab), University of Fribourg, Fribourg, Switzerland; cristian.carmeli@unifr.ch), Arnaud Chiolero, MD PhD, (Population Health Laboratory (#PopHealthLab), University of Fribourg, Fribourg, Switzerland; Institute of Primary Health Care (BIHAM), University of Bern, Bern, Switzerland; Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, Canada; arnaud.chiolero@unifr.ch), Prune Collombet, MSc (Division of Primary Care, Geneva University Hospitals, Geneva, Switzerland; prune.collombet@hcuge.ch), Laurie Corna, PhD (Department of Business Economics, Health & Social Care (DEASS), University of Applied Sciences & Arts of Southern Switzerland (SUPSI), Manno, Switzerland; laurie.corna@supsi.ch), Jenny Crawford, MPH (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; jenny.crawford@uzh.ch), Luca Crivelli, PhD (Department of Business Economics, Health & Social Care (DEASS), University of Applied Sciences & Arts of Southern Switzerland (SUPSI), Manno, Switzerland; Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; luca.crivelli@supsi.ch), Stéphane Cullati, PhD (Population Health Laboratory (#PopHealthLab), University of Fribourg, Fribourg, Switzerland; Department of Readaptation and Geriatrics, Faculty of Medicine, University of Geneva, Switzerland; stephane.cullati@unifr.ch), Alexia Cusini, MD (Infectious Diseases Unit, Cantonal Hospital, 7000 Chur, Switzerland; alexia.cusini@ksgr.ch), Valérie D'Acremont, MD PhD (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; valerie.dacremont@unisante.ch), Carlo De Pietro, PhD (Department of Business Economics, Health & Social Care (DEASS), University of Applied Sciences & Arts of Southern Switzerland (SUPSI), Manno, Switzerland; carlo.depietro@supsi.ch), Agathe Deschamps, MPH (Cantonal Medical Service, Neuchâtel, Switzerland; agathe.deschamps@ne.ch), Yaron Dibner (Population Epidemiology Unit, Primary Care Division, Geneva University Hospitals, Geneva, Switzerland; yaron.diber@hcuge.ch), Sophie Droz, BA (Cantonal Medical Service, Neuchâtel, Switzerland; sophie.droz@ne.ch), Alexis Dumoulin, PhD (Institut central des hôpitaux, Hôpital du Valais, Sion, Switzerland ; alexis.dumoulin@hopitalvs.ch), Olivier Duperrex, MD Msc (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; olivier.duperrex@unisante.ch), Julien Dupraz, MD MAS (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; julien.dupraz@unisante.ch), Malik Egger, MSc (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; malik.egger@unisante.ch), Nathalie Engler, (Cantonal Hospital St. Gallen, Clinic for Infectious Diseases and Hospital Epidemiology, St. Gallen, Switzerland; natalie.engler@kssg.ch), Adina Mihaela Epure, MD (Population Health Laboratory (#PopHealthLab), University of Fribourg, Fribourg, Switzerland; Department of Epidemiology and Health Services, Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; adina-mihaela.epure@unifr.ch), Sandrine Estoppey, MSc (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; sandrine.estoppey@unisante.ch), Marta Fadda, PhD (Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; marta.fadda@usi.ch), Vincent Faivre (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; vincent.faivre@unisante.ch), Jan Fehr, MD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; jan.fehr@usz.ch), Andrea Felappi (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; andrea.felappi@unisante.ch), Maddalena Fiordelli, PhD (Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; maddalena.fiordelli@usi.ch), Antoine Flahault, MD PhD (Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland; Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland; Department of Health and Community Medicine, University of Geneva, Geneva, Switzerland; antoine.flahault@unige.ch), Luc Fornerod, MAS (Observatoire valaisan de la santé (OVS), Sion, Switzerland ; luc.fornerod@ovs.ch), Cristina Fragoso Corti, PhD (Department of environment construction and design (DACD), University of Applied Sciences & Arts of Southern Switzerland (SUPSI), Manno, Switzerland; cristina.fragoso@supsi.ch), Marion Frangville, Msc (Division of Primary Care, Geneva University Hospitals, Geneva, Switzerland; marion.frangville@hcuge.ch), Irène Frank, PhD (Clinical Trial Unit, Cantonal Hospital Luzern, Luzern, Switzerland; irene.frank@luks.ch) Giovanni Franscella, Msc (Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; giovanni.franscella@usi.ch), Anja Frei, PhD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; anja.frei@uzh.ch), Doreen Gille, MSc (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; doreen.gille@uzh.ch), Gisela Michel, PhD (Department of Health Sciences and Medicine, University of Luzern, Luzern, Switzerland; gisela.michel@unilu.ch)Semira Gonseth Nusslé, MSc MD (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; semira.gonseth-nussle@unisante.ch), Auriane Gouzowski, MA (Cantonal Medical Service, Neuchâtel, Switzerland; Auriane.gouzowski@ne.ch), Idris Guessous, MD, PhD (Division of Primary Care, Geneva University Hospitals, Geneva, Switzerland; Department of Health and Community Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland; idris.guessous@hcuge.ch), Julien Guggisberg, BA (Cantonal Medical Service, Neuchâtel, Switzerland; Julien.guggisberg@ne.ch), Huldrych Günthard, MD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; huldrych.guenthard@usz.ch), Felix Gutzwiller, MD, PhD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland), Medea Imboden, PhD (Swiss Tropical and Public Health Institute, Basel, Switzerland, University of Basel, Basel, Switzerland; medea.imboden@swisstph.ch), Loussine Incici, LLM(Cantonal Medical Service, Neuchâtel, Switzerland; loussine.incici@ne.ch), Emilie Jendly (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; emilie.jendly@unisante.ch), Ruedi Jung, Msc (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; ruedi.jung@uzh.ch), Christian Kahlert, MD (Cantonal Hospital St. Gallen, Clinic for Infectious Diseases and Hospital Epidemiology, St. Gallen, Switzerland; Children's Hospital of Eastern Switzerland, Infectious Diseases and Hospital Epidemiology, St. Gallen, Switzerland; christian.kahlert@kssg.ch), Laurent Kaiser, MD PhD (Geneva Center for Emerging Viral Diseases and Laboratory of Virology, Geneva University Hospitals, Geneva, Switzerland; Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland; Department of Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland; laurent.kaiser@hcuge.ch), Laurent Kaufmann, MD (Cantonal Medical Service, Neuchâtel, Switzerland; laurent.kaufmann@ne.ch), Marco Kaufmann, PhD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; marco.kaufmann@uzh.ch), Simone Kessler, (Cantonal Hospital St. Gallen, Clinic for Infectious Diseases and Hospital Epidemiology, St. Gallen, Switzerland; simone.kessler@kssg.ch), Philipp Kohler, MD MSc (Cantonal Hospital St. Gallen, Clinic for Infectious Diseases and Hospital Epidemiology, St. Gallen, Switzerland; philipp.kohler@kssg.ch), Susi Kriemler, MD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; susi.kriemlerwiget@uzh.ch), Lauranne Lenoir, MA (Cantonal Medical Service, Neuchâtel, Switzerland; lauranne.lenoir@ne.ch), Sara Levati, PhD (Department of Business Economics, Health & Social Care (DEASS), University of Applied Sciences & Arts of Southern Switzerland (SUPSI), Manno, Switzerland; sara.levati@supsi.ch), Bettina Maeschli (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; maeschli@corona-immunitas.ch), Jean-Luc Magnin, PhD (Laboratory, HFR-Fribourg, Fribourg, Switzerland; jean-luc.magnin@h-fr.ch), Eric Masserey, MD (Cantonal Medical Office, General Health Department, Canton of Vaud, Lausanne, Switzerland; eric.masserey@vd.ch), Rosalba Morese, PhD (Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; rosalba.morese@usi.ch), Nicolai Mösli, MD (Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; nicolai.moesli@swisstph.ch), Natacha Noël (Population Epidemiology Unit, Primary Care Division, Geneva University Hospitals, Geneva, Switzerland; natacha.noel@hcuge.ch), Maëlle Orhant, BA (Cantonal Medical Service, Neuchâtel, Switzerland), Daniel Henry Paris, MD PhD (Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; daniel.paris@swisstph.ch), Jérôme Pasquier, PhD (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; jerome.pasquier@unisante.ch), Francesco Pennacchio, PhD (Division of Primary Care, Geneva University Hospitals, Geneva, Switzerland; francesco.pennacchio@hcuge.ch), Dusan Petrovic, PhD (Division of Primary Care, Geneva University Hospitals, Geneva, Switzerland; dusan.petrovic@hcuge.ch), Stefan Pfister, PhD (Laboratory, HFR-Fribourg, Fribourg, Switzerland; stefan.pfister@h-fr.ch), Attilio Picazio, PhD (Population Epidemiology Unit, Primary Care Division, Geneva University Hospitals, Geneva, Switzerland), Cesarina Prandi, PhD (Department of Business Economics, Health & Social Care (DEASS), University of Applied Sciences & Arts of Southern Switzerland (SUPSI), Manno, Switzerland; cesarina.prandi@supsi.ch); Giovanni Piumatti, PhD (Institute of Public Health (IPH), Università della Svizzera Italiana (USI), Lugano, Switzerland; Giovanni.Piumatti@unige.ch), Jane Portier (Department of Primary Care, Geneva University Hospitals, Geneva, Switzerland ; jane.portier@hcuge.ch), Nicole Probst-Hensch, Dr. phil.II PhD MPH (Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; nicole.probst@swisstph.ch), Caroline Pugin (Population Epidemiology Unit, Primary Care Division, Geneva University Hospitals, Geneva, Switzerland; caroline.pugin@hcuge.ch), Milo Puhan, MD PhD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; miloalan.puhan@uzh.ch), Thomas Radtke, PhD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; thomas.radtke@uzh.ch), Aude Richard, MD MPH (Division of Primary Care, Geneva University Hospitals, Geneva, Switzerland; Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland; aude.richard@unige.ch), Claude-François Robert, MD (Cantonal Medical Service, Neuchâtel, Switzerland; claude-francois.robert@ne.ch), Pierre-Yves Rodondi, MD (Institute of Family Medicine, University of Fribourg, Fribourg, Switzerland; pierre-yves.rodondi@unifr.ch), Nicholas Rodondi, MD (Institute of Primary Health Care (BIHAM), University of Bern, Switzerland; nicholas.rodondi@biham.unibe.ch), Eric Salberg, BA (Cantonal Medical Service, Neuchâtel, Switzerland; Eric.salberg@ne.ch), Javier Sanchis Zozaya, MD (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; javier.sanchis-zozaya@unisante.ch), Virginie Schlüter, MAS, MD (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; virginie.schlueter@unisante.ch), Valentine Schneider, MSc (Cantonal Medical Service, Neuchâtel, Switzerland; valentine.schneider@ne.ch), Amélie Steiner-Dubuis (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Switzerland; amelie.steiner-dubuis@unisante.ch), Silvia Stringhini, PhD (Division of Primary Care, Geneva University Hospitals, Geneva, Switzerland; silvia.stringhini@hcuge.ch), Johannes Sumer, MD (Cantonal Hospital St. Gallen, Clinic for Infectious Diseases and Hospital Epidemiology, St. Gallen, Switzerland; johannes.sumer@kssg.ch), Ismaël Tall, MA (Cantonal Medical Service, Neuchâtel, Switzerland; Ismael.tall@ne.ch), Julien Thabard (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; julien.thabard@unisante.ch), Mauro Tonolla, PhD (Department of environment construction and design (DACD), University of Applied Sciences & Arts of Southern Switzerland (SUPSI), Manno, Switzerland; mauro.tonolla@supsi.ch), Nicolas Troillet, MD Msc (Institut central des hôpitaux, Hôpital du Valais, Sion, Switzerland ; nicolas.troillet@hopitalvs.ch), Agne Ulyte, MD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; agne.ulyte@uzh.ch), Sophie Vassaux, MSc (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; sophie.vassaux@unisante.ch), Thomas Vermes, Msc (Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland; thomas.vermes@swisstph.ch), Fabian Vollrath, Msc, (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; vollrath@corona-immunitas.ch),Viktor von Wyl, PhD (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; viktor.vonwyl@uzh.ch), Erin West, Msc (Epidemiology, Biostatistics and Prevention Institute, University of Zurich, Zurich, Switzerland; erinashley.west@uzh.ch), Ania Wisniak, MD (Division of Primary Care, Geneva University Hospitals, Geneva, Switzerland; Institute of Global Health, Faculty of Medicine, University of Geneva, Geneva, Switzerland; anna.wisniak@unige.ch), Maria-Eugenia Zaballa, PhD (Population Epidemiology Unit, Primary Care Division, Geneva University Hospitals, Geneva, Switzerland; mariaeugenia.zaballa@hcuge.ch), Claire Zuppinger, MSc (Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland; claire.zuppinger@unisante.ch)