Incidence and Prevalence of Coronavirus Disease 2019 Within a Healthcare Worker Cohort During the First Year of the Severe Acute Respiratory Syndrome Coronavirus 2 Pandemic

• Published in: Clinical infectious diseases Vol. 75; no. 9; pp. 1573 - 1584
• Main Authors: Doernberg, Sarah B, Holubar, Marisa, Jain, Vivek, Weng, Yingjie, Lu, Di, Bollyky, Jenna B, Sample, Hannah, Huang, Beatrice, Craik, Charles S, Desai, Manisha, Rutherford, George W, Maldonado, Yvonne
• Format: Journal Article
• Language: English
• Published: United States 29.10.2022
• Subjects: Cohort Studies; COVID-19 - epidemiology; Health Personnel; Humans; Incidence; Longitudinal Studies; Pandemics - prevention & control; Prevalence; SARS-CoV-2; COVID-19; healthcare personnel; SARS-CoV-2; healthcare worker
• ISSN: 1058-4838; 1537-6591
• DOI: 10.1093/cid/ciac210

Preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2_ infections in healthcare workers (HCWs) is critical for healthcare delivery. We aimed to estimate and characterize the prevalence and incidence of coronavirus disease 2019 (COVID-19) in a US HCW cohort and to identify risk factors associated with infection. 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. A total of 2435 HCWs contributed 768 person-years of follow-up time. We identified 21 of 2435 individuals with prevalent infection, resulting in a baseline prevalence of 0.86% (95% confidence interval [CI], .53%-1.32%). We identified 70 of 2414 incident infections (2.9%), yielding a cumulative incidence rate of 9.11 cases per 100 person-years (95% CI, 7.11-11.52). Community contact with a known COVID-19 case was most strongly correlated with increased hazard for infection (hazard ratio, 8.1 [95% CI, 3.8-17.5]). High-risk work-related exposures (ie, breach in protective measures) drove an association between work exposure and infection (hazard ratio, 2.5 [95% CI, 1.3-4.8). More cases were identified in HCWs when community case rates were high. 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.