SARS-CoV-2 seroprevalence and asymptomatic viral carriage in healthcare workers: a cross-sectional study

Shields, Adrian; Faustini, Sian E; Perez-Toledo, Marisol; Jossi, Sian; Aldera, Erin; Allen, Joel D; Al-Taei, Saly; Backhouse, Claire; Bosworth, Andrew; Dunbar, Lyndsey A; Ebanks, Daniel; Emmanuel, Beena; Garvey, Mark; Gray, Joanna; Kidd, I Michael; McGinnell, Golaleh; McLoughlin, Dee E; Morley, Gabriella; O'Neill, Joanna; Papakonstantinou, Danai; Pickles, Oliver; Poxon, Charlotte; Richter, Megan; Walker, Eloise M; Wanigasooriya, Kasun; Watanabe, Yasunori; Whalley, Celina; Zielinska, Agnieszka E; Crispin, Max; Wraith, David C; Beggs, Andrew D; Cunningham, Adam F; Drayson, Mark T; Richter, Alex G

Abstract

<jats:sec><jats:title>Objective</jats:title><jats:p>To determine the rates of asymptomatic viral carriage and seroprevalence of SARS-CoV-2 antibodies in healthcare workers.</jats:p></jats:sec><jats:sec><jats:title>Design</jats:title><jats:p>A cross-sectional study of asymptomatic healthcare workers undertaken on 24/25 April 2020.</jats:p></jats:sec><jats:sec><jats:title>Setting</jats:title><jats:p>University Hospitals Birmingham NHS Foundation Trust (UHBFT), UK.</jats:p></jats:sec><jats:sec><jats:title>Participants</jats:title><jats:p>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.</jats:p></jats:sec><jats:sec><jats:title>Intervention</jats:title><jats:p>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.</jats:p></jats:sec><jats:sec><jats:title>Main outcome measure</jats:title><jats:p>Proportion of participants demonstrating infection and positive SARS-CoV-2 serology.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>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%, ?<jats:sup>2</jats:sup>=21.1034, p&lt;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).</jats:p></jats:sec><jats:sec><jats:title>Conclusions and relevance</jats:title><jats:p>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.</jats:p></jats:sec>

Citation

Shields, A., Faustini, S. E., Perez-Toledo, M., Jossi, S., Aldera, E., Allen, J. D., …Richter, A. G. (2020). SARS-CoV-2 seroprevalence and asymptomatic viral carriage in healthcare workers: a cross-sectional study. Thorax, 75(12), 1089 - 1094. https://doi.org/10.1136/thoraxjnl-2020-215414

• Journal Article Type: Article
• Acceptance Date: Aug 11, 2020
• Publication Date: Sep 11, 2020
• Journal: Thorax
• Print ISSN: 0040-6376
• Publisher: BMJ Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 75
• Issue: 12
• Pages: 1089 - 1094
• DOI: https://doi.org/10.1136/thoraxjnl-2020-215414
• Publisher URL: https://thorax.bmj.com/content/75/12/1089