Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months: a Danish observational cohort study of 44 000 healthcare workers

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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 et al.

In: Clinical Microbiology and Infection, Vol. 28, No. 5, 05.2022, p. 710-717.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Harvard

Iversen, K, Kristensen, JH, Hasselbalch, RB, Pries-Heje, M, Nielsen, PB, Knudsen, AD, Fogh, K, Norsk, JB, Andersen, O, Fischer, TK, Juul Jensen, CA, Torp-Pedersen, C, Rungby, J, Ditlev, SB, Hageman, I, Møgelvang, R, Gybel-Brask, M, Dessau, RB, Sørensen, E, Harritshøj, L, Folke, F, Sten, C, Engel Møller, ME, Benfield, T, Ullum, H, Jørgensen, CS, Erikstrup, C, Ostrowski, SR, Nielsen, SD & Bundgaard, H 2022, 'Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months: a Danish observational cohort study of 44 000 healthcare workers', Clinical Microbiology and Infection, vol. 28, no. 5, pp. 710-717. https://doi.org/10.1016/j.cmi.2021.09.005

APA

Iversen, K., Kristensen, J. H., Hasselbalch, R. B., Pries-Heje, M., Nielsen, P. B., Knudsen, A. D., Fogh, K., Norsk, J. B., Andersen, O., Fischer, T. K., Juul Jensen, C. A., Torp-Pedersen, C., Rungby, J., Ditlev, S. B., Hageman, I., Møgelvang, R., Gybel-Brask, M., Dessau, R. B., Sørensen, E., ... Bundgaard, H. (2022). Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months: a Danish observational cohort study of 44 000 healthcare workers. Clinical Microbiology and Infection, 28(5), 710-717. https://doi.org/10.1016/j.cmi.2021.09.005

CBE

Iversen K, Kristensen JH, Hasselbalch RB, Pries-Heje M, Nielsen PB, Knudsen AD, Fogh K, Norsk JB, Andersen O, Fischer TK, et al. 2022. Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months: a Danish observational cohort study of 44 000 healthcare workers. Clinical Microbiology and Infection. 28(5):710-717. https://doi.org/10.1016/j.cmi.2021.09.005

MLA

Vancouver

Iversen K, Kristensen JH, Hasselbalch RB, Pries-Heje M, Nielsen PB, Knudsen AD et al. Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months: a Danish observational cohort study of 44 000 healthcare workers. Clinical Microbiology and Infection. 2022 May;28(5):710-717. https://doi.org/10.1016/j.cmi.2021.09.005

Author

Iversen, Kasper ; Kristensen, Jonas Henrik ; Hasselbalch, Rasmus Bo et al. / Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months : a Danish observational cohort study of 44 000 healthcare workers. In: Clinical Microbiology and Infection. 2022 ; Vol. 28, No. 5. pp. 710-717.

Bibtex

@article{9bd0933eb05148f8bb53fbcff4260867,
title = "Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months: a Danish observational cohort study of 44 000 healthcare workers",
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 = "COVID, Healthcare workers, Immune response, SARS-CoV-2, Seroprevalence",
author = "Kasper Iversen and Kristensen, {Jonas Henrik} and Hasselbalch, {Rasmus Bo} and Mia Pries-Heje and Nielsen, {Pernille Brok} and Knudsen, {Andreas Dehlb{\ae}k} and Kamille Fogh and Norsk, {Jakob Boesgaard} and Ove Andersen and Fischer, {Thea K{\o}hler} and {Juul Jensen}, {Claus Antonio} and Christian Torp-Pedersen and J{\o}rgen Rungby and Ditlev, {Sisse Bolm} and Ida Hageman and Rasmus M{\o}gelvang and Mikkel Gybel-Brask and Dessau, {Ram B.} and Erik S{\o}rensen and Lene Harritsh{\o}j and Fredrik Folke and Curt Sten and {Engel M{\o}ller}, {Maria Elizabeth} and Thomas Benfield and Henrik Ullum and J{\o}rgensen, {Charlotte Sv{\ae}rke} and Christian Erikstrup and Ostrowski, {Sisse R.} and Nielsen, {Susanne Dam} and Henning Bundgaard",
year = "2022",
month = may,
doi = "10.1016/j.cmi.2021.09.005",
language = "English",
volume = "28",
pages = "710--717",
journal = "Clinical Microbiology and Infection",
issn = "1198-743X",
publisher = "Elsevier Ltd",
number = "5",

}

RIS

TY - JOUR

T1 - Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through 6 months

T2 - a Danish observational cohort study of 44 000 healthcare workers

AU - Iversen, Kasper

AU - Kristensen, Jonas Henrik

AU - Hasselbalch, Rasmus Bo

AU - Pries-Heje, Mia

AU - Nielsen, Pernille Brok

AU - Knudsen, Andreas Dehlbæk

AU - Fogh, Kamille

AU - Norsk, Jakob Boesgaard

AU - Andersen, Ove

AU - Fischer, Thea Køhler

AU - Juul Jensen, Claus Antonio

AU - Torp-Pedersen, Christian

AU - Rungby, Jørgen

AU - Ditlev, Sisse Bolm

AU - Hageman, Ida

AU - Møgelvang, Rasmus

AU - Gybel-Brask, Mikkel

AU - Dessau, Ram B.

AU - Sørensen, Erik

AU - Harritshøj, Lene

AU - Folke, Fredrik

AU - Sten, Curt

AU - Engel Møller, Maria Elizabeth

AU - Benfield, Thomas

AU - Ullum, Henrik

AU - Jørgensen, Charlotte Sværke

AU - Erikstrup, Christian

AU - Ostrowski, Sisse R.

AU - Nielsen, Susanne Dam

AU - Bundgaard, Henning

PY - 2022/5

Y1 - 2022/5

N2 - 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.

AB - 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.

KW - COVID

KW - Healthcare workers

KW - Immune response

KW - SARS-CoV-2

KW - Seroprevalence

UR - http://www.scopus.com/inward/record.url?scp=85116788811&partnerID=8YFLogxK

U2 - 10.1016/j.cmi.2021.09.005

DO - 10.1016/j.cmi.2021.09.005

M3 - Journal article

C2 - 34543759

AN - SCOPUS:85116788811

VL - 28

SP - 710

EP - 717

JO - Clinical Microbiology and Infection

JF - Clinical Microbiology and Infection

SN - 1198-743X

IS - 5

ER -