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Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months: a Danish observational cohort study of 44 000 healthcare workers.
Iversen, Kasper; Kristensen, Jonas Henrik; Hasselbalch, Rasmus Bo; Pries-Heje, Mia; Nielsen, Pernille Brok; Knudsen, Andreas Dehlbæk; Fogh, Kamille; Norsk, Jakob Boesgaard; Andersen, Ove; Fischer, Thea Køhler; Juul Jensen, Claus Antonio; Torp-Pedersen, Christian; Rungby, Jørgen; Ditlev, Sisse Bolm; Hageman, Ida; Møgelvang, Rasmus; Gybel-Brask, Mikkel; Dessau, Ram B; Sørensen, Erik; Harritshøj, Lene; Folke, Fredrik; Sten, Curt; Engel Møller, Maria Elizabeth; Benfield, Thomas; Ullum, Henrik; Jørgensen, Charlotte Sværke; Erikstrup, Christian; Ostrowski, Sisse R; Nielsen, Susanne Dam; Bundgaard, Henning.
  • Iversen K; Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Borgmester Ib Juuls Vej 1, 2730, Herlev, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Emergency Medicine, Copenhagen University Hospital-Herlev and Gentofte, Borgme
  • Kristensen JH; Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Borgmester Ib Juuls Vej 1, 2730, Herlev, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Emergency Medicine, Copenhagen University Hospital-Herlev and Gentofte, Borgme
  • Hasselbalch RB; Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Borgmester Ib Juuls Vej 1, 2730, Herlev, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Emergency Medicine, Copenhagen University Hospital-Herlev and Gentofte, Borgme
  • Pries-Heje M; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Cardiology, Copenhagen University Hospital-Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
  • Nielsen PB; Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Borgmester Ib Juuls Vej 1, 2730, Herlev, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Emergency Medicine, Copenhagen University Hospital-Herlev and Gentofte, Borgme
  • Knudsen AD; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Cardiology, Copenhagen University Hospital-Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark; Department of Infectious Disease, Copenhagen University Hospital-Rigshospitalet, Blegdamsvej 9, 2100, Cop
  • Fogh K; Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Borgmester Ib Juuls Vej 1, 2730, Herlev, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Emergency Medicine, Copenhagen University Hospital-Herlev and Gentofte, Borgme
  • Norsk JB; Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Borgmester Ib Juuls Vej 1, 2730, Herlev, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Emergency Medicine, Copenhagen University Hospital-Herlev and Gentofte, Borgme
  • Andersen O; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Emergency and Department of Clinical Research, Copenhagen University Hospital-Amager og Hvidovre, Kettegård Alle 30, 2650, Hvidovre, Denmark.
  • Fischer TK; Department of Clinical Research, Copenhagen University Hospital-Nordsjællands Hospital, Dyrehavevej 29, 3400, Hillerød, Denmark; Department of Public Health, University of Copenhagen, Copenhagen, Denmark.
  • Juul Jensen CA; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Biochemistry, Copenhagen University Hospital-Nordsjællands Hospital, Dyrehavevej 29, 3400, Hillerød, Denmark.
  • Torp-Pedersen C; Department of Clinical Research, Copenhagen University Hospital-Nordsjællands Hospital, Dyrehavevej 29, 3400, Hillerød, Denmark; Department of Public Health, University of Copenhagen, Copenhagen, Denmark.
  • Rungby J; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Endocrinology and Copenhagen Center for Translational Research, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Bispebjerg Bakke 23, 2400, København NV, Denmark.
  • Ditlev SB; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Pulmonary Medicine and Copenhagen Center for Translational Research, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark.
  • Hageman I; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Mental Health Services-The Capital Region of Denmark, Kristineberg 3, 2100, København Ø, Denmark.
  • Møgelvang R; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Cardiology, Copenhagen University Hospital-Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
  • Gybel-Brask M; Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Inge Lehmans Vej 7, 2100, Copenhagen, Denmark.
  • Dessau RB; Department of Clinical Microbiology, Zealand University Hospital-Slagelse, Ingemannsvej 46, 4200, Slagelse, Denmark; University of Southern Denmark, Odense, Denmark.
  • Sørensen E; Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Inge Lehmans Vej 7, 2100, Copenhagen, Denmark.
  • Harritshøj L; Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Inge Lehmans Vej 7, 2100, Copenhagen, Denmark.
  • Folke F; Department of Cardiology, Copenhagen University Hospital-Herlev and Gentofte, Borgmester Ib Juuls Vej 1, 2730, Herlev, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Copenhagen University Hospital-Copenhagen Emergency Medical Services, Copenhagen, Denmark; C
  • Sten C; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Diagnostisk Enhed, Copenhagen University Hospital-Bornholm, Ullasvej 8, 3700, Rønne, Denmark.
  • Engel Møller ME; Department of Infectious Disease, Copenhagen University Hospital-Amager and Hvidovre, Kettegaard Alle 30, 2650 Hvidovre, Denmark.
  • Benfield T; Department of Infectious Disease, Copenhagen University Hospital-Amager and Hvidovre, Kettegaard Alle 30, 2650 Hvidovre, Denmark.
  • Ullum H; Statens Serum Institut, Artillerivej 5, 2300, København S, Copenhagen, Denmark.
  • Jørgensen CS; Statens Serum Institut, Artillerivej 5, 2300, København S, Copenhagen, Denmark.
  • Erikstrup C; Department of Clinical Immunology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus, Denmark.
  • Ostrowski SR; Department of Clinical Immunology, Copenhagen University Hospital-Rigshospitalet, Inge Lehmans Vej 7, 2100, Copenhagen, Denmark.
  • Nielsen SD; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Disease, Copenhagen University Hospital-Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
  • Bundgaard H; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Cardiology, Copenhagen University Hospital-Rigshospitalet, Blegdamsvej 9, 2100, Copenhagen, Denmark.
Clin Microbiol Infect ; 28(5): 710-717, 2022 May.
Article in English | MEDLINE | ID: covidwho-1415294
ABSTRACT

OBJECTIVES:

Antibodies to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are a key factor in protecting against coronavirus disease 2019 (COVID-19). We examined longitudinal changes in seroprevalence in healthcare workers (HCWs) in Copenhagen and the protective effect of antibodies against SARS-CoV-2.

METHODS:

In this prospective study, screening for antibodies against SARS-CoV-2 (ELISA) was offered to HCWs three times over 6 months. HCW characteristics were obtained by questionnaires. The study was registered at ClinicalTrials.gov, NCT04346186.

RESULTS:

From April to October 2020 we screened 44 698 HCWs, of whom 2811 were seropositive at least once. The seroprevalence increased from 4.0% (1501/37 452) to 7.4% (2022/27 457) during the period (p < 0.001) and was significantly higher than in non-HCWs. Frontline HCWs had a significantly increased risk of seropositivity compared to non-frontline HCWs, with risk ratios (RRs) at the three rounds of 1.49 (95%CI 1.34-1.65, p < 0.001), 1.52 (1.39-1.68, p < 0.001) and 1.50 (1.38-1.64, p < 0.001). The seroprevalence was 1.42- to 2.25-fold higher (p < 0.001) in HCWs from dedicated COVID-19 wards than in other frontline HCWs. Seropositive HCWs had an RR of 0.35 (0.15-0.85, p 0.012) of reinfection during the following 6 months, and 2115 out of 2248 (95%) of those who were seropositive during rounds one or two remained seropositive after 4-6 months. The 133 of 2248 participants (5.0%) who seroreverted were slightly older and reported fewer symptoms than other seropositive participants.

CONCLUSIONS:

HCWs remained at increased risk of infection with SARS-CoV-2 during the 6-month period. Seropositivity against SARS-CoV-2 persisted for at least 6 months in the vast majority of HCWs and was associated with a significantly lower risk of reinfection.
Keywords

Full text: Available Collection: International databases Database: MEDLINE Type of study: Etiology study / Observational study / Risk factors Language: English Journal: Clin Microbiol Infect Journal subject: Communicable Diseases / Microbiology Year: 2022 Document Type: Article

Full text: Available Collection: International databases Database: MEDLINE Type of study: Etiology study / Observational study / Risk factors Language: English Journal: Clin Microbiol Infect Journal subject: Communicable Diseases / Microbiology Year: 2022 Document Type: Article