Risk factors for detection of SARS-CoV-2 in healthcare workers during April 2020 in a UK hospital testing programme

Background: Healthcare workers (HCW) are a crucial part of the workforce but are also at potentially at increased risk of infection from SARS-CoV-2. Emerging evidence has suggested specific groups of HCW are at further increased risk particularly those from Black, Asian and Minority Ethnic (BAME) groups. Previous reports have not examined risk factors associated with contracting the virus and were reported prior to the pandemic peak in the UK. Methods: Staff testing in our facility commenced on the 1st April and all individuals were entered into a database. Repeat testing was used for the first 3 weeks for those initially testing negative. Demographics including age, sex, occupation and ethnicity were recorded. Occupation was divided into acute frontline (e.g. ITU), frontline, clinical support staff and non-clinical staff. Final testing status was analysed using univariate and multivariable analysis to determine independent associations with age, sex, occupation and ethnicity. Findings: 991 individuals (mean age 42.6 years, 145 males) were tested over a 4 week period and overall 440/991 (43.4%) tested positive for SARS-CoV-2. SARS-CoV-2 RNA detection rates were significantly higher in the first week of testing (59.0%) compared to week 2 (odds ratio 0.59), week 3 (odds ratio 0.32) and week 4 (odds ratio 0.23)(all p<0.001). Multivariable analysis showed no increased risk SARS-CoV-2 RNA detection with age (odds ratio 1.01, 95% confidence interval 0.99 - 1.03, p = 0.22), male sex (OR 1.03, 95% CI 0.59 - 1.79, p = 0.92), acute frontline work (OR 0.79, 95% CI 0.53 - 1.17, p = 0.23) or BAME status (OR 1.08, 95% CI 0.56 - 2.07, p = 0.84). Interpretation: A robust healthcare worker testing strategy is a crucial component of managing the workforce during the SARS-CoV-2 pandemic. No specific variables were identified that altered the risk of SARS-CoV-2 RNA detection including age, sex, occupation and ethnicity.