Taking on a contentious issue with a thorough analysis, researchers found during the pre-vaccine pandemic in 2020 that 11.5% of healthcare workers who acquired COVID-19 in their hospital were occupationally infected. Thus, as has often been observed by employee health professionals, the lion’s share of exposures and SARS-CoV-2 infections in hospital staff have occurred in the community.1

“Recommendations were changing constantly, at least in the beginning,” said Aimee Russell, MLS(ASCP), CIC, an infection preventionist at St. Luke’s Health System in Boise, ID. “There were PPE [personal protective equipment] shortages, and we were making decisions that were completely unheard of in infection prevention, like reusing PPE. Things were uncertain. For our staff, it was kind of scary at times. Our staff needed to know that the decisions we were making were keeping them safe, and we needed to know that we were making the right decisions.”

Russell and her colleague, Jessi Bond, MPH, CIC, recently presented the findings at the Association of Professionals in Infection Control and Epidemiology 2021 virtual conference.

Russell and Bond used a communicable disease reporting process through workers’ compensation between March 1, 2020, and Aug. 31, 2020, to determine workplace exposure and transmission. The number of COVID-19-positive patients was extracted from employee health laboratory reports.1

They found 693 COVID-19-related exposures for the period, with 85 of those testing positive. Fifty-one employees acquired SARS-CoV-2 from a workplace exposure, including 26 patient exposures, 14 co-worker exposures, six patient and co-worker exposures, and five unknown exposures. A total of 441 positive cases were found, with workplace acquisition accounting for 11.6% of the employee cases.

“We felt the best way to track this was to look at our workplace acquisitions, because in the end, keeping people safe is our ultimate concern, but we needed a way to be able to do it,” Russell said. “After the first couple of discussions with [the infection control committee], we recognized we actually had an existing infectious disease reporting process through our employee safety and our workers’ compensation program that would fit the need. We actually had no idea this program existed. That was a really good reminder for us that if we can get out of our silos that occur in large organizations, we can find resources we didn’t even know existed, and we can save ourselves from reinventing all kinds of wheels.”

Thus, workplace exposure and transmission of COVID-19 were determined in part using this established process, which directs employees to use an incident reporting system for occupational injury and illness. Employees also were asked to report possible exposures.

“Information then was gathered directly from the employee regarding their potential work and non-work exposure sources, and that was then provided to the occupational health physician,” Russell said. “The physician would review the information and then advise the workers’ compensation department if the information available supports that the employee contracted COVID-19 in the course of their work duties at St. Luke’s.”

Of course, reliance on self-reporting was a limitation of the study, as was the lack of information on compliance with PPE.

“I would say anecdotally during this time, infection prevention was also doing patient exposure contact tracing and that also involved interviewing of staff directly,” Russell said. “What we were seeing matched very closely with the data that we were collecting from the workers’ compensation process. For the most part, what we found is staff had a really good idea of where they got COVID-19. They knew what their exposure source was.”

The level of COVID-19 in the community also was factored in. These numbers fluctuated, but could be an indicator of enhanced risk of exposure and infection beyond work.

“When our community levels rose, so did our employee cases,” she says. “However, our workplace exposures stayed low and sporadic. But sometimes our staff tend to forget that COVID actually spreads quite well in a break room. That [realization] helped us identify if clusters were occurring.”

During the study period, there were no known exposure sources for five infected healthcare workers. Ultimately, these were determined to be occupational cases, contributing to the higher percentage of 11.6% out of the larger total of 441 positive cases.

“It was determined that it was more likely these employees acquired the virus from some type of exposure in the workplace,” Bond says. “[Still], we have concluded that the vast majority of employees acquired COVID-19 from exposures outside of work.”


  1. Bond JM, Russell A. Utilizing worker’s compensation claims to assess SARS-CoV-2 transmission in healthcare workers at a large health system. Am J Infect Control 2021;49:S10.