Coworkers are more likely than patients to transmit SARS-CoV-2 infection to healthcare personnel

Objectives To compare the impact of occupational exposures to SARS-CoV-2 positive patients and SARS-CoV-2 positive coworkers, by comparing the frequency of occupational exposure incidents and the rate of healthcare personnel (HCP) who developed a positive PCR test for SARS-COV-2 after occupational exposure to the two different types of infectious individuals. Methods A retrospective analysis of all confirmed higher risk occupational exposure incidents that occurred in HCP from 20 March 2020 to 31 December 2020 at a large multisite US academic medical centre. Comparisons between groups for source type were performed using unpaired Student's t-test for continuous variables and the χ 2 test for categorical variables, regression analysis was conducted to assess the associations between source type and risk of positive COVID-19 test after occupational exposure. Results In total, 2253 confirmed medium or high-risk occupational exposures occurred during the study period. 57% were exposures from coworker sources. Each source individual exposed a mean of 2.6 (95% CI 2.3 to 2.9) HCP; during postexposure surveillance, 4.5% of exposed HCP tested positive within 14 days. A coworker source on average exposed 2.2 (95% CI 2.01 to 2.4) other HCP and infected 0.14 (95% CI 0.1 to 0.17) HCP, while patient sources exposed a mean of 3.4 (95% CI 2.6 to 4.2) HCP but only infected 0.07 (95% CI 0.04 to 0.11) HCP. The multivariate analysis demonstrated that exposure to a coworker source carried a higher risk of testing positive compared with exposure to a patient source (OR 3.22; 95% CI 1.72 to 6.04). Conclusion Occupational exposures to coworker sources were not only more frequent but also associated with triple the risk of developing COVID-19 infection, compared with exposures to patient sources.