Background Healthcare workers (HCW) are presumed to be at increased risk of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection due to occupational exposure to infected patients. However, there has been little epidemiological research to assess these risks. Methods We conducted a prospective cohort study of HCW (n = 546) and non-healthcare workers (NHCW; n = 283) with no known prior SARS-CoV-2 infection who were recruited from a large U.S. university and two affiliated university hospitals. In this cross-sectional analysis of data collected at baseline, we examined SARS-CoV-2 infection status (as determined by presence of SARS-CoV-2 RNA in oropharyngeal swabs) by healthcare worker status and role. Results At baseline, 41 (5.0%) of the participants tested positive for SARS-CoV-2 infection, of whom 14 (34.2%) reported symptoms. The prevalence of SARS-CoV-2 infection was higher among HCW (7.3%) than in NHCW (0.4%), representing a 7.0% greater absolute risk (95% confidence interval for risk difference 4.7, 9.3%). The majority of infected HCW (62.5%) were nurses. Positive tests increased across the two weeks of cohort recruitment in line with rising confirmed cases in the hospitals and surrounding counties. Conclusions Overall, our results demonstrate that HCW had a higher prevalence of SARS-CoV-2 infection than NHCW. Continued follow-up of this cohort will enable us to monitor infection rates and examine risk factors for transmission.

Findings:The prevalence of SARS-CoV-2 infection was 7.3% in healthcare workers and 0.4% in nonhealthcare workers, representing 7.0% greater absolute risk in the former (95% confidence interval for risk difference 4.7%, 9.3%). Infections were most common among nursing staff.Meaning: Health care workers, particularly those with high levels of close patient contact, may be particularly vulnerable to SARS-CoV-2 infection. Additional strategies are needed to protect these critical frontline workers. Abstract:Importance: Healthcare workers are presumed to be at increased risk of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection due to occupational exposure to infected patients. However, no epidemiological study has examined the prevalence of SARS-CoV-2 infection in a cohort of healthcare workers during the early phase of community transmission. Objective:To determine the baseline prevalence of SARS-CoV-2 infection in a cohort of previously undiagnosed healthcare workers and a comparison group of non-healthcare workers. Design: Prospective cohort studySetting: A large U.S. university and two affiliated university hospitals Participants: 546 health care workers and 283 non-health care workers with no known prior SARS-CoV-2 infection Exposure: Healthcare worker status and role Main outcome(s) and measure(s): SARS-CoV-2 infection status as determined by presence of SARS-CoV-2 RNA in oropharyngeal swabs.

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Background We studied risk factors, antibody responses, and symptoms of SARS-CoV-2 infection in a diverse, ambulatory population. Methods A prospective cohort (n=831, including 548 hospital-based healthcare workers) previously undiagnosed with SARS-CoV-2 infection was followed for six months with serial testing (SARS-CoV-2 PCR, specific IgG) and surveys. Results 93 participants (11.2%) tested SARS-CoV-2-positive; 14 (15.1%) were asymptomatic and 24 (25.8%), severely symptomatic. Healthcare workers were more likely to become infected (14.2% vs. 5.3%, aOR 2.1, 95% CI 1.4-3.3) and have severe symptoms (29.5% vs. 6.7%). IgG antibodies were detected after 79% of asymptomatic infections, 89% with mild-moderate symptoms, and 96% with severe symptoms. IgG trajectories after asymptomatic infection (slow increases) differed from symptomatic infections (early peaks within 2 months). Most participants (92%) had persistent IgG responses (median 171 days). In multivariable models, IgG titers were positively associated with symptom severity, certain comorbidities, and hospital work. Dyspnea, altered smell and taste, and other neurologic changes persisted for ≥120 days in ≥10% of affected participants. Participants with prolonged symptoms (generally more severely symptomatic) had higher antibody levels. Conclusions In a prospective, ethnically diverse cohort, symptom severity correlated with the magnitude and trajectory of IgG production. Symptoms frequently persisted for many months after infection.