Sept 23, 2020
Reviewed by Daniel Mendoza, M.D., Ph.D.
In a recent Lancet Public Health study, Nguyen et al. assessed the risk of COVID-19 among front-line health care workers (HCWs) compared with the general population and the effect of personal protective equipment (PPE) on this risk in the U.K. and U.S.
The investigators conducted an observational cohort study of the general community, including HCWs, using self-reported data from a smartphone application (the COVID Symptom Study) between March and April 2020. Participants provided information on demographic factors, medical history, and subsequently reported any COVID-19 symptoms. Follow-up began when participants first reported on the app and continued until a report of a positive COVID-19 test or the time of last data entry, whichever occurred first. Cox proportional hazards modelling was used to estimate multivariate-adjusted hazard ratios (HRs) of the primary outcome, which was a positive COVID-19 test. Covariates included sex, race/ethnicity, diabetes, heart disease, lung disease, kidney disease, smoking, and body mass index.
The investigators enrolled 2,035,395 community individuals and 99,795 HCWs. They found 5,545 incident reports of a positive COVID-19 test over 34,435,272 person-days. The median follow-up was 18.9 days. Compared with community individuals, HCWs were at increased risk for reporting a positive COVID-19 test (adjusted HR 11.6, 95% confidence interval [CI] 10.9–12.3). This increased risk remained significant after adjusting for differences in testing frequency between HCWs and community individuals (adjusted HR 3.40, 95% CI 3.37–3.43).
Secondary and post-hoc analysis indicated that Black, Asian, and minority ethnic HCWs had an increased risk of COVID-19 (adjusted HR 1.8, 95% CI 1.5–2.2) compared with non-Hispanic White HCWs. Non-White HCWs more frequently reported reuse of, or inadequate access to, PPE after adjusting for exposure to patients with COVID-19 (adjusted OR 1.5, 95% CI 1.4–1.6).
HCWs who reported PPE reuse had an increased risk of a positive COVID-19 test compared with HCWs who reported adequate PPE (adjusted HR 1.5, 95% CI 1.2–1.8). Notably, among HCWs who reported adequate PPE, the risk for COVID-19 was increased for those caring for patients with suspected COVID-19 (adjusted HR 2.4, 95% CI 1.9–3) and for those caring for patients with documented COVID-19 (4.8, 4–5.9), compared with HCWs who did not care for either group.
Compared with the risk for community individuals, the risk for HCWs was increased in all health care settings, but was highest for those working in inpatient settings (adjusted HR 24.3, 95% CI 21.8–27.1) and nursing homes (16.2, 13.9–19.7).
In conclusion, the risk of reporting a positive test for COVID-19 was increased among HCWs compared with community individuals. Health care systems should ensure adequate availability of PPE and develop further strategies to protect HCWs from COVID-19, particularly those from Black, Asian, and minority ethnic backgrounds, and those who work in inpatient settings and nursing homes.
