Sarah B Doernberg1, Marisa Holubar2, Vivek Jain3, Yingjie Weng4, Di Lu4, Jenna B Bollyky5, Hannah Sample6, Beatrice Huang7, Charles S Craik8, Manisha Desai4, George W Rutherford9, Yvonne Maldonado5. 1. Division of Infectious Diseases, University of California, San Francisco (UCSF). 2. Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine. 3. Division of HIV, Infectious Diseases & Global Medicine, San Francisco General Hospital, University of California, San Francisco (UCSF). 4. Quantitative Sciences Unit, Stanford University School of Medicine. 5. Division of Pediatric Infectious Diseases, Stanford University School of Medicine. 6. Department of Biochemistry and Biophysics (UCSF). 7. Department of Family and Community Medicine, San Francisco General Hospital, University of California, San Francisco (UCSF). 8. Department of Pharmaceutical Chemistry (UCSF). 9. Division of Infectious Disease and Global Epidemiology, Department of Epidemiology and Biostatistics, UCSF.
Abstract
BACKGROUND: Preventing SARS-CoV2 infections in healthcare workers (HCWs) is critical for healthcare delivery. We aimed to estimate and characterize the prevalence and incidence of COVID-19 in a US HCW cohort and to identify risk factors associated with infection. METHODS: We conducted a longitudinal cohort study of HCWs at 3 Bay Area medical centers using serial surveys and SARS-CoV-2 viral and orthogonal serological testing, including measurement of neutralizing antibodies. We estimated baseline prevalence and cumulative incidence of COVID-19. We performed multivariable Cox proportional hazards models to estimate associations of baseline factors with incident infections and evaluated the impact of time-varying exposures on time to COVID-19 using marginal structural models. RESULTS: 2435 HCWs contributed 768 person years of follow-up time. We identified 21/2435 individuals with prevalent infection, resulting in a baseline prevalence of 0.86% (95% CI, 0.53% to 1.32%). We identified 70/2414 (2.9%) incident infections yielding a cumulative incidence rate of 9.11 cases per 100 person years (95% CI 7.11 to 11.52). Community contact with a known COVID-19 case most strongly correlated with increased hazard for infection (HR 8.1, 95% CI, 3.8, 17.5). High-risk work-related exposures (i.e., breach in protective measures) drove an association between work exposure and infection (HR 2.5, 95% CI, 1.3-4.8). More cases were identified in HCW when community case rates were high. CONCLUSION: We observed modest COVID-19 incidence despite consistent exposure at work. Community contact was strongly associated with infections but contact at work was not unless accompanied by high-risk exposure.
BACKGROUND: Preventing SARS-CoV2 infections in healthcare workers (HCWs) is critical for healthcare delivery. We aimed to estimate and characterize the prevalence and incidence of COVID-19 in a US HCW cohort and to identify risk factors associated with infection. METHODS: We conducted a longitudinal cohort study of HCWs at 3 Bay Area medical centers using serial surveys and SARS-CoV-2 viral and orthogonal serological testing, including measurement of neutralizing antibodies. We estimated baseline prevalence and cumulative incidence of COVID-19. We performed multivariable Cox proportional hazards models to estimate associations of baseline factors with incident infections and evaluated the impact of time-varying exposures on time to COVID-19 using marginal structural models. RESULTS: 2435 HCWs contributed 768 person years of follow-up time. We identified 21/2435 individuals with prevalent infection, resulting in a baseline prevalence of 0.86% (95% CI, 0.53% to 1.32%). We identified 70/2414 (2.9%) incident infections yielding a cumulative incidence rate of 9.11 cases per 100 person years (95% CI 7.11 to 11.52). Community contact with a known COVID-19 case most strongly correlated with increased hazard for infection (HR 8.1, 95% CI, 3.8, 17.5). High-risk work-related exposures (i.e., breach in protective measures) drove an association between work exposure and infection (HR 2.5, 95% CI, 1.3-4.8). More cases were identified in HCW when community case rates were high. CONCLUSION: We observed modest COVID-19 incidence despite consistent exposure at work. Community contact was strongly associated with infections but contact at work was not unless accompanied by high-risk exposure.
Authors: Roger Chou; Tracy Dana; David I Buckley; Shelley Selph; Rongwei Fu; Annette M Totten Journal: Ann Intern Med Date: 2022-07-12 Impact factor: 51.598