{
  "abstract": "Background: Healthcare workers (HCWs) faced increased SARS-CoV-2 infection risk. We aimed to identify factors associated with SARS-CoV-2 infection in HCWs and assess how their association with infection changed over time to prepare for future similar events.\n\nMethods: We conducted a cohort study among HCWs from 18 European hospitals that completed weekly questionnaires and tested weekly/fortnightly by PCR. We defined separate cohorts for pre-Omicron (May 2021–December 2021), pandemic Omicron (December 2021–April 2023), and post-pandemic Omicron (September 2023–April 2024) periods. Using Cox proportional hazards models, we estimated adjusted hazard ratios (aHRs) for associations between each exposure and SARS-CoV-2 infection, adjusting for age, sex, underlying conditions, and hospital.\n\nResults: We included 1395, 2056, and 1254 HCWs in the three periods. Median age was 44 years, and 2597 (80%) were female, 740 (22%) medical doctors, 1399 (42%) nurses, 391 (12%) administrative personnel, 113 (3%) ancillary personnel, and 612 (18%) worked in other roles. Compared to medical doctors, ancillary personnel presented the highest risk pre-Omicron (aHR 3.86, 95% CI [1.30, 11.47]). Household contact was the strongest risk factor pre-Omicron (aHR 4.05 95% CI [1.78, 9.19]) but decreased over time.\n\nConclusions: Household exposure and occupational role were key risk factors, but their effect size decreased over time. Infection prevention strategies should be regularly updated, extending beyond clinical staff and considering household exposure, should similar events occur.\n\nClinical trial number: Not applicable.\n\nSupplementary Information: The online version contains supplementary material available at https://doi.org/10.1186/s12879-026-14127-3.",
  "abstract_shown": true,
  "affiliations": [
    "Epiconcept, 25 Rue Titon, Paris, 75011 France",
    "European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden",
    "Croatian Institute of Public Health (HZJZ), Zagreb, Croatia",
    "University of Tartu, Tartu, Estonia",
    "St. James’s Hospital, Dublin, Ireland",
    "Department of Clinical Medicine, Trinity College, Dublin, Ireland",
    "Galway University Hospital, Galway, Ireland",
    "University of Milano, Bicocca, Italy",
    "Fondazione IRCCS San Gerardo dei Tintori, Bicocca, Italy",
    "Università Cattolica del Sacro Cuore, Rome, Italy",
    "Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy",
    "Pauls Stradins University Hospital, Riga, Latvia",
    "Children Clinical University Hospital, Riga, Latvia",
    "National Institute of Medicine of the Ministry of Interior and Administration, Warsaw, Poland",
    "Department of Epidemiology, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal",
    "Dr Victor Babes Clinical Hospital of Infectious and Tropical Diseases, Bucharest, Romania",
    "National Institute for Mother and Child Care Alessandrescu Rusescu, Bucharest, Romania",
    "Central Military Emergency University Hospital Dr Carol Davila, Bucharest, Romania",
    "Institut de Recerca Sant Joan de Deu. Hospital Sant Joan de Deu, Bucharest, Spain",
    "Medicine Department, Universitat Internacional de Catalunya, Barcelona, Spain",
    "Ciber of Epidemiology and Public Health CIBERESP, Madrid, Spain",
    "IIS Aragon - Miguel Servet University Hospital, Zaragoza, Spain",
    "Viljandi Hospital, Viljandi, Estonia",
    "Cantacuzino National Military-Medical Institute for Research and Development, Bucharest, Romania",
    "Department of Occupational Risk Prevention, Hospital Sant Joan de Deu, Barcelona, Spain",
    "Department of Infectious Diseases, National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal",
    "National Institute of Health Doutor Ricardo Jorge, Lisbon, Portugal",
    "Health Board, Tallinn, Estonia",
    "Health Protection Surveillance Centre, Lisbon, Portugal"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 108,
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      "name": "Iris Ganser"
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      "name": "Madelyn Rojas-Castro"
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      "name": "Kim Brolin"
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      "name": "Catherine Fleming"
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        8
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      "name": "Rita Murri"
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      "name": "Viesturs Zvirbulis"
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      "name": "Dace Zavadska"
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      "name": "Konstanty Szuldrzynski"
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      "name": "Vânia Gaio"
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      "name": "Liis Lohur"
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      "name": "Anna Spolti"
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        9,
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      "name": "Kathleen De Gaetano Donati"
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      "name": "Ilze Abolina"
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      "name": "Dagne Gravele"
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        14
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      "name": "Ausenda Machado"
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      "name": "Simin Aysel Florescu"
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      "name": "Mihaela Lazar"
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      "name": "Pilar Subirats Cid"
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      "name": "Laura Clusa"
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      "name": "Gordan Sarajlić"
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      "name": "Jacklyn Sui"
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      "name": "Claire Kenny"
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      "name": "Rosaria Santangelo"
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      "name": "Dainis Krievins"
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        12
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      "name": "Elza Anna Bārzdiņa"
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        25
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      "name": "Camila Valadas Henriques"
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        15
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      "name": "Alma Gabriela Kosa"
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    {
      "affs": [
        16
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      "name": "Victor Daniel Miron"
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    {
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        17
      ],
      "name": "Săftica-Mariana Pohrib"
    },
    {
      "affs": [
        18,
        19,
        20
      ],
      "name": "Carmen Muñoz-Almagro"
    },
    {
      "affs": [
        21
      ],
      "name": "Ana Maria Milagro"
    },
    {
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        0
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      "name": "Anthony Nardone"
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        1
      ],
      "name": "Sabrina Bacci"
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    {
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        0
      ],
      "name": "Camelia Savulescu"
    },
    {
      "affs": [
        0
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      "name": "Hanna Sepp"
    },
    {
      "affs": [
        26
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      "name": "Hanna Sepp"
    },
    {
      "affs": [
        27
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      "name": "Lisa Domegan"
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    {
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        27
      ],
      "name": "Joan O’Donell"
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    {
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        6
      ],
      "name": "Maeve Kernan"
    },
    {
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        4
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      "name": "Anne Moriarty"
    },
    {
      "affs": [
        4
      ],
      "name": "Conor Moran"
    },
    {
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      "name": "Giulia De Angelis"
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      "name": "Giulia Menchinelli"
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      "name": "Cinzia Recine"
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      "name": "Silvia Zelli"
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      "name": "Benedetta Falasca"
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      "name": "Silvia Lamonica"
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      "name": "Zrinka Bošnjak"
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  "bibtex": "https://research.draconitic.com/paper/cx3rd20dcc36r.bib",
  "cited_by": 0,
  "doi": "10.1186/s12879-026-14127-3",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13737939/",
  "id": "cx3rd20dcc36r",
  "issns": [
    "1471-2334"
  ],
  "landing_url": "https://doi.org/10.1186/s12879-026-14127-3",
  "language": "en",
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Research"
    ],
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      "openalex",
      "2725|SARS-CoV-2 and COVID-19 Research"
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  "openalex": "W7201886386",
  "pdf_url": null,
  "pmcid": "PMC13737939",
  "pmid": "42983287",
  "published": "2026-08-07",
  "publisher": "BMC",
  "ris": "https://research.draconitic.com/paper/cx3rd20dcc36r.ris",
  "sources": [
    {
      "first_seen": "2026-11-09T12:23:01Z",
      "native_id": "PMC13737939",
      "source": "pmc",
      "url": "https://doi.org/10.1186/s12879-026-14127-3"
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  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2725|SARS-CoV-2 and COVID-19 Research",
      "subfield": "infectious-disease"
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  "title": "Factors associated with SARS-CoV-2 infection among healthcare workers: a European multicentre cohort study, May 2021–April 2024",
  "title_text": "Factors associated with SARS-CoV-2 infection among healthcare workers: a European multicentre cohort study, May 2021–April 2024",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T12:23:01Z",
  "url": "https://research.draconitic.com/paper/cx3rd20dcc36r",
  "venue": "BMC Infectious Diseases",
  "versions": []
}