U.S. health care workers were most likely to be infected with COVID-19 at work during the pandemic’s first year, according to a new study that challenges previous research suggesting their risk was highest off the job.

Researchers said their findings could help guide efforts to better protect health care workers during future infectious disease outbreaks.

“This study provides important insights to guide infection prevention and control practices in health care settings so that we can better protect HCPs [health care professionals] and their patients,” said Linda Dickey, president of the Association for Professionals in Infection Control and Epidemiology (APIC), which published the findings in its journal.

For the study, researchers analyzed data from the U.S. Centers for Disease Control and Prevention on nearly 84,000 health care workers who were diagnosed with COVID-19 between March 1, 2020, and March 31, 2021, and whose source of exposure was known.

Exposure to SARS-CoV-2 was more likely in the workplace (52%) than in the home (nearly 31%) or community (about 26%). Workplace-associated exposures peaked in April 2020 at 84%, the researchers found.

About two-thirds of health care workers who reported a specific type of on-the-job exposure said they’d come into contact with patients or other health care workers who had COVID-19.

The largest reductions in workplace exposures occurred in June 2020 after introduction of improved infection prevention and control measures, and in December 2020, after launch of the nationwide COVID-19 health care worker vaccination program.

Increases in community rates of COVID-19 were associated with greater numbers of health care workers reporting workplace exposure and fewer reporting household or community exposure.

The findings were published online April 13 in the American Journal of Infection Control.

“Our findings suggest that, particularly during periods of high community incidence of COVID-19, HCP exposures occur both at the workplace and outside of it, with the workplace being a major driver of infections,” said first author Rachael Billock of the CDC’s COVID-19 Response Team.

“These results emphasize the continued need for improved infection prevention and control measures in occupational settings, as well as the need for improved surveillance to identify and reduce occupational exposures to SARS-CoV-2,” she added.

As of May 2021, at least 500,000 COVID-19 diagnoses and 1,653 deaths among U.S. health care workers were reported to the CDC, and those numbers are known to be lower than the actual levels.

In addition, APIC president Dickey said, the study “reiterates the importance of collecting data on HCP work-related variables, such as industry, occupation, and workplace exposures, in infectious disease surveillance.”

More information

The U.S. Department of Labor has guidance for employers and health care workers on preventing COVID in the workplace.

SOURCE: Association for Professionals in Infection Control and Epidemiology, news release, April 14, 2022