- This study involved 99,795 frontline health care providers and 2,035,395 members of the general population who were enrolled in the U.S. or the U.K. between March 24 and April 23, 2020, and used the COVID Symptom Study app
- Health care providers had at least a threefold increased risk of reporting a positive COVID-19 test, compared with the general public, even after adjustment for other risk factors
- Black, Asian and minority ethnic health care providers had between a 5- and 22-fold greater risk of COVID-19 compared with the non-Hispanic white general public
- Increased susceptibility to infection was evident even among health care providers who reported having adequate personal protective equipment
Frontline health care providers—those who have direct patient contact—account for 10%–20% of all COVID-19 diagnoses, according to initial estimates. Using a smartphone application that's being applied in other studies, Long H. Nguyen, MD, MS, instructor in the Division of Gastroenterology at Massachusetts General Hospital, and Andrew T. Chan, MD, MPH, director for Cancer Epidemiology in the Mass General Cancer Center, chief of the Clinical and Translational Epidemiology Unit (CTEU) in the Department of Medicine, and vice chief for clinical research in the Division of Gastroenterology, and colleagues confirmed that risk of COVID-19 is higher for frontline providers than the general population—even for those who reported adequate personal protective equipment (PPE).
In The Lancet Public Health, the researchers add that the risk is especially high among Black, Asian and minority ethnic health care providers.
The prospective, population-based study made use of the free COVID Symptom Study app (previously known as COVID Symptom Tracker), developed by Zoe Global in collaboration with Mass General and King's College London. It guides participants in reporting baseline demographic information and comorbidities, daily information on symptoms and results of any COVID-19 testing. The app was previously described in detail in Science.
This analysis compared 99,795 frontline health care providers with 2,035,395 members of the general population who were enrolled in the U.S. or the U.K. between March 24 and April 23, 2020. The participants provided 24.4 million entries over median follow-up of 19 days.
Providers vs. General Population
Multivariable analysis showed health care providers were much more likely than the general population to have a positive COVID-19 test:
- Overall—HR, 11.61; 95% CI, 10.93–12.33
- U.K.—HR, 12.52; 95% CI, 11.77–13.31
- U.S.—HR, 2.80; 95% CI, 2.09–3.75 (P <.0001 for difference from U.K.)
The risk was higher among health care providers even after the researchers accounted for the likelihood that they had greater access to testing.
Impact of Race/Ethnicity
Compared with the non-HIspanic white general population overall, the risk of a positive COVID-19 test was increased for:
- Individuals from Black, Asian and minority ethnic backgrounds in the general population (HR, 2.51)
- Black, Asian and minority ethnic health care providers (HR, 21.88)
- White health care providers (HR, 12.58)
Black, Asian and minority ethnic health care providers had nearly double the risk of COVID-19 compared with white health care providers (HR, 1.81).
Impact of Clinical Setting and Access to PPE
Even among health care providers reporting adequate PPE, the risk of COVID-19 was higher among those caring for patients with suspected or documented COVID-19 than for those who had no exposure to patients with COVID-19.
The risk related to PPE was greatest for providers in inpatient settings (where providers most frequently reported PPE reuse) and nursing homes (where providers most frequently reported inadequate PPE).
Non-white health care providers were 49% more likely than whites to report reuse of or inadequate access to PPE, even after adjustment for exposure to patients with COVID-19. At the time of this study, disinfection of PPE before reuse was uncommon.
Clearly, health care providers can contribute to community spread of COVID-19. Because transmission is most likely when providers are asymptomatic or mildly symptomatic, frequent testing in health care settings is justified.
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