key: cord-0832374-qwgwct1y
authors: Brunner, Wendy M.; Hirabayashi, Liane; Krupa, Nicole L.; Scribani, Melissa B.; Jenkins, Paul; Clark, Stephen D.; May, John J.; Gadomski, Anne M.
title: Severe acute respiratory coronavirus virus 2 (SARS-CoV-2) IgG results among healthcare workers in a rural upstate New York hospital system
date: 2020-10-26
journal: Infect Control Hosp Epidemiol
DOI: 10.1017/ice.2020.1296
sha: 7247c42c5f4b14dee55d06e14a6236b61d378cb9
doc_id: 832374
cord_uid: qwgwct1y

nan

Among 764 employees tested, 15 were positive for SARS-CoV-2 IgG antibodies, for a seroprevalence of 2.0%, compared to 4.5% for patients (ie, 34 seropositives among 762 tested). Of the 764 employees tested, 601 (78.7%) completed the study questionnaire.

Seroprevalence among all study participants was 12 of 601 (2.0%) and 4 of 130 (3.1%) in the random sample. The mean IgG level was 4.93 (range, 2.10-8.14) among seropositives and 0.06 (range, 0.01-1.17) among seronegatives. One-third of seropositives reported a positive PCR test, 8 .3% reported a negative PCR test, and 58.3% had no PCR test. Of the 589 seronegative employees, 47 reported having a PCR test (all negative).

Seropositive employees were just as likely as seronegative employees to report having no direct contact with COVID-19 patients (25.0% vs 17.7%; P = 0.46) ( Table 1) . Seropositive employees were less likely to report involvement in high-risk patientrelated tasks, such as COVID-19 testing, although these differences were not statistically significant.

There were no statistically significant differences by serology status among employees reporting travel outside of the region or social distancing practices. Seropositive employees were more likely than seronegative employees to report having a known or suspected COVID-19 case in their household (41.7% vs 10.9%, P = .0072), and they were just as likely as seronegative employees to report living with an essential services worker who continued to work outside the home (50.0% vs 51.4%; P = .53). Although more seropositive employees had contact outside of work with a known or suspected COVID-19 contact, this difference was not statistically significant (41.7% vs 31.6%; P = .13).

Two-thirds of the seropositive employees (66.7%) reported a COVID-19-like illness since January 1, 2020, compared with 44.9% of seronegative employees, however this difference was not statistically significant (P = .13). Of the seropositive employees, 4 (33.3%) were asymptomatic. Among the 258 seronegative employees reporting COVID-19-like illness, 56 stated that their symptoms ended in January or February. Seropositive and seronegative employees showed different profiles in symptoms; seropositive employees were more likely to report sore throat, dry cough, and headache. 

Our findings among employees in a rural healthcare network show that direct patient care was not associated with increased likelihood of COVID-19 infection and that seropositivity was more likely associated with nonwork exposures. Similar findings have been reported in urban, densely populated settings and larger medical centers. [3] [4] [5] [6] [7] Although travel, social-distancing practices, and having an essential-services worker in the household did not differ by antibody status in our study, being exposed to a COVID-19 contact outside of work or in the same household was positively correlated with antibody status. This study is potentially limited by the timing between COVID-19 exposure and the antibody test. Employees tested >2-3 months following COVID-19 infection may no longer have detectable levels of IgG antibodies, thereby underestimating the prevalence of previous employee infection. [8] [9] [10] Other limitations include sampling and recall bias. Employee antibody testing was not done entirely at random; therefore, the estimate of seropositivity reported may not be representative of all employees. Also, seropositive employees may have been more likely to accurately recall potential exposures to COVID-19.

Finally, due to the low prevalence of seropositivity, statistical comparisons between seropositive and seronegative employees had limited statistical power.

During government-mandated shelter-in-place orders, SARS-CoV-2 IgG seroprevalence among employees in a rural healthcare network was lower than for the community at large. In this rural region, healthcare workers were more likely to be exposed to COVID-19 outside of the workplace than on the job. Thus, it is important that healthcare workers maintain high vigilance regarding potential nonwork exposures as well as healthcare-related patient-care exposures. 

Performance characteristics of the Abbott Architect SARS-CoV-2 IgG assay and seroprevalence in

Performance characteristics of four high-throughput immunoassays for detection of IgG antibodies against SARS-CoV-2

Seroprevalence of antibodies against SARS-CoV-2 among healthcare workers in a large Spanish reference hospital

Anesthesiologists' and intensive care providers' exposure to COVID-19 infection in a New York City academic center: a prospective cohort study assessing symptoms and COVID-19 antibody testing

SARS-CoV-2-specific antibody detection in healthcare workers in Germany with direct contact to COVID-19 patients

Hospital-wide SARS-CoV-2 antibody screening in 3056 staff in a tertiary center in Belgium

Seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection among VA healthcare system employees suggests higher risk of infection when exposed to SARS-CoV-2 outside of the work environment

Detection of IgG antibody during the follow-up in patients with COVID-19 infection

Change in antibodies to SARS-CoV-2 over 60 days among health care personnel in

Rapid decay of anti-SARS-CoV-2 antibodies in persons with mild COVID-19

Acknowledgments. We thank the following: Bassett Healthcare Network