Abstract
Objective: To determine the rates of asymptomatic viral carriage and seroprevalence of SARS-CoV-2 antibodies in healthcare workers.
Design: A cross-sectional study of asymptomatic healthcare workers undertaken on 24/25 April 2020.
Setting: University Hospitals Birmingham NHS Foundation Trust (UHBFT), UK.
Participants: 545 asymptomatic healthcare workers were recruited while at work. Participants were invited to participate via the UHBFT social media. Exclusion criteria included current symptoms consistent with COVID-19. No potential participants were excluded.
Intervention: Participants volunteered a nasopharyngeal swab and a venous blood sample that were tested for SARS-CoV-2 RNA and anti-SARS-CoV-2 spike glycoprotein antibodies, respectively. Results were interpreted in the context of prior illnesses and the hospital departments in which participants worked.
Main outcome measure: Proportion of participants demonstrating infection and positive SARS-CoV-2 serology.
Results: The point prevalence of SARS-CoV-2 viral carriage was 2.4% (n=13/545). The overall seroprevalence of SARS-CoV-2 antibodies was 24.4% (n=126/516). Participants who reported prior symptomatic illness had higher seroprevalence (37.5% vs 17.1%, χ 2 =21.1034, p<0.0001) and quantitatively greater antibody responses than those who had remained asymptomatic. Seroprevalence was greatest among those working in housekeeping (34.5%), acute medicine (33.3%) and general internal medicine (30.3%), with lower rates observed in participants working in intensive care (14.8%). BAME (Black, Asian and minority ethnic) ethnicity was associated with a significantly increased risk of seropositivity (OR: 1.92, 95% CI 1.14 to 3.23, p=0.01). Working on the intensive care unit was associated with a significantly lower risk of seropositivity compared with working in other areas of the hospital (OR: 0.28, 95% CI 0.09 to 0.78, p=0.02).
Conclusions and relevance: We identify differences in the occupational risk of exposure to SARS-CoV-2 between hospital departments and confirm asymptomatic seroconversion occurs in healthcare workers. Further investigation of these observations is required to inform future infection control and occupational health practices.
Original language | English |
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Pages (from-to) | 1089-1094 |
Number of pages | 6 |
Journal | Thorax |
Volume | 75 |
Issue number | 12 |
Early online date | 11 Sept 2020 |
DOIs | |
Publication status | Published - 1 Dec 2020 |
Bibliographical note
Funding Information: This study was funded internally by the University of Birmingham and University Hospitals Birmingham NHS Foundation Trust and carried out at the National Institute for Health Research (NIHR)/Wellcome Trust Birmingham Clinical Research Facility. This paper presents independent research supported by the NIHR Birmingham Biomedical Research Centre at the University Hospitals Birmingham NHS Foundation Trust and the University of Birmingham. Laboratory studies were undertaken by the Clinical Immunology Service, University of Birmingham. Work in MC’s laboratory was funded by the International AIDS Vaccine Initiative, Bill and Melinda Gates Foundation through the Collaboration for AIDS Vaccine Discovery (OPP1084519 and OPP1115782), the Scripps Consortium for HIV Vaccine Development (CHAVD) (AI144462), and the University of Southampton Coronavirus Response Fund which has over 1000 donors from around the world. ADB is currently supported by a Cancer Research UK Advanced Clinician Scientist award (C31641/ A23923) and his laboratory is supported by CRUK Centre Birmingham (C17422/ A25154) and the Birmingham Experimental Cancer Medicine Centre (C11497/ A25127).Open Access: This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See: https://creativecommons.org/licenses/by/4.0/.
Publisher Copyright: © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.
Citation: Shields A, Faustini SE, Perez-Toledo M, et al. SARS-CoV-2 seroprevalence and asymptomatic viral carriage in healthcare workers: a cross-sectional study. Thorax 2020;75:1089-1094.
DOI: http://dx.doi.org/10.1136/thoraxjnl-2020-215414
Keywords
- clinical epidemiology
- infection control
- respiratory infection
- viral infection