SARS-CoV-2 Seroprevalence and Asymptomatic Viral Carriage in Healthcare Workers: A Cross-sectional Study
September 11, 2020
Volume and Number
thoraxjnl-2020-215414. doi: 10.1136/thoraxjnl-2020-215414. Epub ahead of print.
Shields A, Faustini SE, Perez-Toledo M, Jossi S, Aldera E, Allen JD, Al-Taei S, Backhouse C, Bosworth A, Dunbar LA, Ebanks D, Emmanuel B, Garvey M, Gray J, Kidd IM, McGinnell G, McLoughlin DE, Morley G, O'Neill J, Papakonstantinou D, Pickles O, Poxon C, Richter M, Walker EM, Wanigasooriya K, Watanabe Y, Whalley C, Zielinska AE, Crispin M, Wraith DC, Beggs AD, Cunningham AF, Drayson MT, Richter AG
To determine the rates of asymptomatic viral carriage and seroprevalence of SARS-CoV-2 antibodies in healthcare workers, across-sectional study of asymptomatic healthcare workers was undertaken on 24/25 April 2020 at University Hospitals Birmingham by the NHS Foundation Trust (UHBFT), United Kingdom. A total of 545 asymptomatic healthcare workers were recruited while at work and invited to participate via the UHBFT social media. Exclusion criteria included current symptoms consistent with COVID-19. No potential participants were excluded. 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. The main outcome was focused on measuring the proportion of participants demonstrating infection and positive SARS-CoV-2 serology. Results revealed that 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%, χ2=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).
- The primary focus of this study was to ascertain key rates of asymptomatic viral carriage and seroprevalence of SARS-CoV-2 antibodies in UK healthcare workers.
- Findings indicate that the point prevalence of SARS-CoV-2 viral carriage was 2.4% and the overall seroprevalence of SARS-CoV-2 antibodies was 24.4%.
- Critically, the study also reveals differences in the risk of exposure of healthcare workers to SARS-CoV-2 between ethnic groups and between hospital departments.
- These findings may inform future infection control and occupational health policy.