Factors associated with SARS-CoV-2 infection among healthcare workers: a European multicentre cohort study, May 2021–April 2024

@article{ganser2026factors,
  title = {{Factors associated with SARS-CoV-2 infection among healthcare workers: a European multicentre cohort study, May 2021–April 2024}},
  author = {Iris Ganser and Madelyn Rojas-Castro and Kim Brolin and Zvjezdana Lovrić Makarić and Anneli Uusküla and Colm Bergin and Catherine Fleming and Paolo Bonfanti and Rita Murri and Viesturs Zvirbulis and Dace Zavadska and Konstanty Szuldrzynski and Vânia Gaio and Corneliu Petro Popescu and Mihai Craiu and Raluca-Maria Hrișcă and Maria Cisneros Perez and Miriam Latorre-Millán and Goranka Petrović and Liis Lohur and Jonathan McGrath and Liam Townsend and Anna Spolti and Kathleen De Gaetano Donati and Ilze Abolina and Dagne Gravele and Ausenda Machado and Simin Aysel Florescu and Mihaela Lazar and Pilar Subirats Cid and Laura Clusa and Gordan Sarajlić and Jacklyn Sui and Claire Kenny and Rosaria Santangelo and Dainis Krievins and Elza Anna Bārzdiņa and Camila Valadas Henriques and Alma Gabriela Kosa and Victor Daniel Miron and Săftica-Mariana Pohrib and Carmen Muñoz-Almagro and Ana Maria Milagro and Anthony Nardone and Sabrina Bacci and Camelia Savulescu and Hanna Sepp and Hanna Sepp and Lisa Domegan and Joan O’Donell and Maeve Kernan and Anne Moriarty and Conor Moran and Giulia De Angelis and Giulia Menchinelli and Cinzia Recine and Silvia Zelli and Benedetta Falasca and Silvia Lamonica and Zrinka Bošnjak},
  journal = {BMC Infectious Diseases},
  year = {2026},
  month = aug,
  doi = {10.1186/s12879-026-14127-3},
  url = {https://doi.org/10.1186/s12879-026-14127-3},
  note = {CC BY-NC-ND 4.0},
}

TY  - JOUR
TI  - Factors associated with SARS-CoV-2 infection among healthcare workers: a European multicentre cohort study, May 2021–April 2024
AU  - Iris Ganser
AU  - Madelyn Rojas-Castro
AU  - Kim Brolin
AU  - Zvjezdana Lovrić Makarić
AU  - Anneli Uusküla
AU  - Colm Bergin
AU  - Catherine Fleming
AU  - Paolo Bonfanti
AU  - Rita Murri
AU  - Viesturs Zvirbulis
AU  - Dace Zavadska
AU  - Konstanty Szuldrzynski
AU  - Vânia Gaio
AU  - Corneliu Petro Popescu
AU  - Mihai Craiu
AU  - Raluca-Maria Hrișcă
AU  - Maria Cisneros Perez
AU  - Miriam Latorre-Millán
AU  - Goranka Petrović
AU  - Liis Lohur
AU  - Jonathan McGrath
AU  - Liam Townsend
AU  - Anna Spolti
AU  - Kathleen De Gaetano Donati
AU  - Ilze Abolina
AU  - Dagne Gravele
AU  - Ausenda Machado
AU  - Simin Aysel Florescu
AU  - Mihaela Lazar
AU  - Pilar Subirats Cid
AU  - Laura Clusa
AU  - Gordan Sarajlić
AU  - Jacklyn Sui
AU  - Claire Kenny
AU  - Rosaria Santangelo
AU  - Dainis Krievins
AU  - Elza Anna Bārzdiņa
AU  - Camila Valadas Henriques
AU  - Alma Gabriela Kosa
AU  - Victor Daniel Miron
AU  - Săftica-Mariana Pohrib
AU  - Carmen Muñoz-Almagro
AU  - Ana Maria Milagro
AU  - Anthony Nardone
AU  - Sabrina Bacci
AU  - Camelia Savulescu
AU  - Hanna Sepp
AU  - Hanna Sepp
AU  - Lisa Domegan
AU  - Joan O’Donell
AU  - Maeve Kernan
AU  - Anne Moriarty
AU  - Conor Moran
AU  - Giulia De Angelis
AU  - Giulia Menchinelli
AU  - Cinzia Recine
AU  - Silvia Zelli
AU  - Benedetta Falasca
AU  - Silvia Lamonica
AU  - Zrinka Bošnjak
PY  - 2026
DA  - 2026/08/07
JO  - BMC Infectious Diseases
DO  - 10.1186/s12879-026-14127-3
UR  - https://doi.org/10.1186/s12879-026-14127-3
AB  - 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.  Methods: 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.  Results: 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.  Conclusions: 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.  Clinical trial number: Not applicable.  Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1186/s12879-026-14127-3.
SN  - 1471-2334
ER  -