Differential occupational risks to healthcare workers from SARS-CoV-2: A prospective observational study
Eyre D., Lumley S., O’Donnell D., Campbell M., Sims E., Lawson E., Warren F., James T., Cox S., Howarth A., Doherty G., Hatch S., Kavanagh J., Chau K., Fowler P., Swann J., Volk D., Yang-Turner F., Stoesser N., Matthews P., Dudareva M., Davies T., Shaw R., Peto L., Downs L., Vogt A., Amini A., Young B., Drennan P., Mentzer A., Skelly D., Karpe F., Neville M., Andersson M., Brent A., Jones N., Ferreira LM., Christott T., Marsden B., Hoosdally S., Cornall R., Crook D., Stuart D., Screaton G., Peto TEA., Holthof B., O’Donnell A-M., Ebner D., Conlon C., Jeffery K., Walker T., Oxford University Hospitals Staff Testing Group None.
Background Personal protective equipment (PPE) and social distancing are designed to mitigate risk of occupational SARS-CoV-2 infection in hospitals. Why healthcare workers nevertheless remain at increased risk is uncertain. Methods We conducted voluntary Covid-19 testing programmes for symptomatic and asymptomatic staff at a UK teaching hospital using nasopharyngeal PCR testing and immunoassays for IgG antibodies. A positive result by either modality determined a composite outcome. Risk-factors for Covid-19 were investigated using multivariable logistic regression. Results 1083/9809(11.0%) staff had evidence of Covid-19 at some time and provided data on potential risk-factors. Staff with a confirmed household contact were at greatest risk (adjusted odds ratio [aOR] 4.63 [95%CI 3.30-6.50]). Higher rates of Covid-19 were seen in staff working in Covid-19-facing areas (21.2% vs. 8.2% elsewhere) (aOR 2.49 [2.00-3.12]). Controlling for Covid-19-facing status, risks were heterogenous across the hospital, with higher rates in acute medicine (1.50 [1.05-2.15]) and sporadic outbreaks in areas with few or no Covid-19 patients. Covid-19 intensive care unit (ICU) staff were relatively protected (0.46 [0.29-0.72]). Positive results were more likely in Black (1.61 [1.20-2.16]) and Asian (1.58 [1.34-1.86]) staff, independent of role or working location, and in porters and cleaners (1.93 [1.25-2.97]). Contact tracing around asymptomatic staff did not lead to enhanced case identification. 24% of staff/patients remained PCR-positive at ≥6 weeks post-diagnosis. Conclusions Increased Covid-19 risk was seen in acute medicine, among Black and Asian staff, and porters and cleaners. A bundle of PPE-related interventions protected staff in ICU.