Conversion Rates to COVID-19 Infection Among Exposed Healthcare Workers

Objectives: To determine the percentage of exposed healthcare workers who converted to COVID-19 after exposure to an individual with COVID-19, and to describe the venue of exposure and time to conversion among healthcare workers at an academic health system. Methods: 1,749 healthcare workers who self-reported a significant COVID-19 exposure from June 10, 2020 to November 30, 2020 were quarantined or could be allowed to work while wearing a mask, and tested at least once by day 14 from time of exposure. Exposure was defined as being within six feet from a person with COVID-19 for more than 15 minutes without a face covering. Venues of exposure were categorized by either household, community, or workplace. Results: 290 (17%) of 1,749 converted to COVID-19 in a median of 4.1 days (range: 1–13). The median days to conversion by venue of exposure were four for household, and community, and five for workplace. Between September 1, 2020 to November 30, 2020, the percentage of healthcare workers who converted to COVID-19 by venue of exposure was 26% (N=159), 18% (N=75), and 10% (N=14) for household, community and workplace exposure, respectively. Conclusion: The conversion rate to COVID-19 among healthcare workers after an exposure was relatively low, but was higher in household exposures and lowest in the workplace.