Objective: To better understand COVID-19 transmission among healthcare workers (HCW), we investigated occupational and non-occupational risk factors associated with cumulative COVID-19 incidence among a Massachusetts HCW cohort. Design, setting, and participants: The retrospective cohort study included adult HCWs in a single healthcare system from March 9 to June 3, 2020. Methods: Participants' SARS-CoV-2 nasopharyngeal RT-PCR results and demographics were de-identified and extracted from an established occupational health, COVID-19 database at the healthcare system. HCWs from each particular job grouping had been categorized into frontline/non-frontline workers. Incidence rate ratio (IRR) and odds ratio were used to compare subgroups after excluding HCWs involved in early infection clusters before universal masking. A sensitivity analysis was performed comparing jobs with the greatest potential occupational risks with others. Results: 152 out of 5177 (2.94%) HCWs were diagnosed with COVID-19. Affected HCWs resided in areas with higher community attack rates (median: 1755.2 vs. 1412.4 cases per 100,000, P<0.001)(multivariate-adjusted IRR: 1.89, 95%CI: 1.03-3.44 comparing 5th to 1st quintile of community rates). After multivariate adjustment, African Americans and Hispanics had higher incidence than non-Hispanic white HCWs (IRR: 2.78, 95%CI: 1.78-4.33; and IRR: 2.41, 95%CI: 1.42-4.07, respectively). After adjusting for race and residential rates, frontline HCWs had a higher IRR (1.73, 95%CI: 1.16-2.54) compared to non-frontline HCWs overall, but not within specific job categories, nor when comparing the highest risk jobs to others. Conclusions: After universal masking was instituted, the strongest risk factors associated with HCWs' COVID-19 infection were residential community infection rate and race.
All Science Journal Classification (ASJC) codes
- Microbiology (medical)
- Infectious Diseases