Research
Print page Print page
Switch language
Rigshospitalet - a part of Copenhagen University Hospital
E-pub ahead of print

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

Research output: Contribution to journalJournal articleResearchpeer-review

  1. The effect of migration on the incidence and mortality of bloodstream infection: a Danish register-based cohort study

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. 2020 List of human papillomavirus assays Suitable for primary cervical cancer screening

    Research output: Contribution to journalReviewResearchpeer-review

  3. Repeated introduction and spread of the MRSA clone t304/ST6 in Northern Europe

    Research output: Contribution to journalJournal articleResearchpeer-review

  4. Invasive aspergillosis in patients with severe COVID-19 pneumonia

    Research output: Contribution to journalLetterResearchpeer-review

  1. Switch to INSTIs, but Not Long-Term Stable INSTIs, Is Associated With Excess Weight Gain in People Living With HIV

    Research output: Contribution to journalLetterResearchpeer-review

  2. HIV infection is associated with type 2 diabetes mellitus

    Research output: Contribution to journalLetterResearchpeer-review

  3. Antibody-dependent neutralizing capacity of the SARS-CoV-2 vaccine BNT162b2 with and without previous COVID-19 priming

    Research output: Contribution to journalJournal articleResearchpeer-review

  4. Capsid-like particles decorated with the SARS-CoV-2 receptor-binding domain elicit strong virus neutralization activity

    Research output: Contribution to journalJournal articleResearchpeer-review

View graph of relations

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.

Original languageEnglish
JournalClinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases
ISSN1198-743X
DOIs
Publication statusE-pub ahead of print - 17 Sep 2021

    Research areas

  • COVID, Healthcare workers, Immune response, SARS-CoV-2, Seroprevalence

ID: 67655661