Study Reveals the Risk of COVID-19 Infection Among Health Care Workers

In an analysis of information from the U.K. and U.S., frontline health care workers had a nearly 12-times higher risk of testing positive for COVID-19 compared with individuals in the general community, and those workers with inadequate access to personal protective equipment (PPE) had an even higher risk. The study, which was conducted by a team led by researchers at Massachusetts General Hospital, King’s College London and Zoe Global Ltd. is available in medRxiv.

Health care workers on the front lines of the battle against COVID-19 face a high risk of becoming infected and are confronted with the possibility of not only getting sick and dying, but also of bringing the infection home to their families and contributing to spread in their communities. “The limited availability of adequate PPE, such as masks, gowns and gloves, has raised concerns about whether our health care system is able to fully protect our health care workers,” said senior author Andrew T. Chan, MD, PhD, Chief of the Clinical and Translational Epidemiology Unit at Mass General and Director of Cancer Epidemiology at the Mass General Cancer Center. “We conducted this study to understand the magnitude of risk for health care workers and what the impact of PPE shortages might be on infection rates.”

For the study, the investigators used a novel smartphone app—called the COVID Symptom Tracker— to examine the risk of testing positive for COVID-19 and/or developing symptoms associated with infection among 2,135,190 individuals in the U.K. and the U.S. between March 24 and April 23, 2020.

Among 2,035,395 community individuals and 99,795 frontline health care workers, 5,545 new reports of a positive COVID-19 test were documented. Compared with the general community, frontline health care workers had an 11.6-times higher risk of testing positive and those who reported that they had inadequate access to PPE had a 23% higher risk. Also, compared with health care workers reporting adequate PPE who did not care for patients with COVID-19, workers caring for patients with documented COVID-19 had a nearly 5-times higher risk of testing positive if they had adequate PPE and a nearly 6-times higher risk if they had inadequate PPE.

The finding that health care workers have a substantially higher risk of COVID-19 infection supports the importance of providing adequate supplies of PPE to those on the front lines. “However, adequate supplies of PPE are not enough to completely protect workers taking care of COVID-19 patients—we also need to focus our energy on making sure that health care workers are trained in the proper use of PPE and that the PPE is high quality,” said Dr. Chan. “We also must be vigilant about implementing other infection control measures to minimize infection of health care workers, including promptly and effectively testing and isolating COVID-19 patients and ensuring that the patient care environment is adequately disinfected.”

Funding Statement

Zoe provided in kind support for all aspects of building, running and supporting the tracking app and service to all users worldwide. King’s College of London investigators (KAL, MNL, TV, MG, CHS, MJC, SO, CJS, TDS) were supported by the Wellcome Trust and EPSRC (WT212904/Z/18/Z, WT203148/Z/16/Z, WT213038/Z/18/Z), the NIHR GSTT/KCL Biomedical Research Centre, MRC/BHF (MR/M016560/1), the NIHR, and the Alzheimer’s Society (AS-JF-17-011). ATC is the Stuart and Suzanne Steele MGH Research Scholar and Stand Up to Cancer scientist. The National Institutes of Health grants related to this project include: UM1 CA186107 (MJS), U01 CA176726 (AHE, WCW), U01 CA167552 (WCW, LAM), U01 HL145386 (JEC), R24 ES028521 (JEC), P30ES000002 (JEH), and a National Institute for Occupational Safety and Health grant contract 200-2017-M-94186 (JEC). An Evergrande COVID-19 Response Fund Award through the Massachusetts Consortium on Pathogen Readiness (MassCPR) supported MGH investigators (LHN, DAD, ADJ, CGG, WM, RSM, DRS, CHL, SK, MS, ATC).

About the Massachusetts General Hospital

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The Mass General Research Institute conducts the largest hospital-based research program in the nation, with annual research operations of over $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments. In August 2019, the Mass General was named #2 in the U.S. News & World Report list of "America’s Best Hospitals."