key: cord-0798950-1jyapgkm
authors: Menting, T.; Krause, K.; Benz-Tettey, F.; Boehringer, R.; Laufer, D.; Gruber, B.; Crump, M.; Schieferdecker, R.; Reuhl, S.; Kaeferstein, A.; Engelhart, S.; Streeck, H.; Marx, B.; Aldabbagh, S.; Eis-Hübinger, A.; Rockstroh, J.K.; Schwarze-Zander, C.
title: Low-threshold SARS-CoV-2 testing facility for hospital staff: prevention of COVID-19 outbreaks?
date: 2020-10-22
journal: Int J Hyg Environ Health
DOI: 10.1016/j.ijheh.2020.113653
sha: 8e961a28bf58d57254e6679d9142095849635db7
doc_id: 798950
cord_uid: 1jyapgkm

BACKGROUND: The ongoing global SARS-CoV-2 pandemic has caused over 4.7 million infections greatly challenging healthcare workers (HCW) and medical institutions worldwide. The SARS-CoV-2 pandemic has shown to significantly impact mental and physical health of HCW. Thus, implementation of testing facilities supporting HCW are urgently needed. METHODS: A low-threshold SARS-CoV-2 testing facility was introduced at the University Hospital Bonn, Germany, in March 2020. Irrespective of clinical symptoms employees were offered a voluntary and free SARS-CoV-2 test. Furthermore, employees returning from SARS-CoV-2 risk regions and employees after risk contact with SARS-CoV-2 infected patients or employees were tested for SARS-CoV-2 infection. Pharyngeal swabs were taken and reverse transcription polymerase chain reaction for detection of SARS-CoV-2 was performed, test results being available within 24 hours. Profession, symptoms and reason for SARS-CoV-2 testing of employees were recorded. RESULTS: Between 9th March and 30th April 2020, a total of 1,510 employees were tested for SARS-CoV-2 infection. 1,185 employees took advantage of the low-threshold testing facility. One percent (n=11) were tested positive for SARS-CoV-2 infection, 18% being asymptomatic, 36% showing mild and 36% moderate/severe symptoms (missing 10%). Furthermore, of 56 employees returning from SARS-CoV-2 risk regions, 18% (10/56) were tested SARS-CoV-2 positive. After risk contact tracking by the hospital hygiene 6 patient-to-employee transmissions were identified in 163 employees with contact to 55 SARS-CoV-2 positive patients. CONCLUSION: In the absence of easily accessible public SARS-CoV-2 testing facilities low-threshold SARS-CoV-2 testing facilities in hospitals with rapid testing resources help to identify SARS-CoV-2 infected employees with absent or mild symptoms, thus stopping the spread of infection in vulnerable hospital environments. High levels of professional infection prevention training and implementation of specialized wards as well as a perfectly working hospital hygiene network identifying and tracking risk contacts are of great importance in a pandemic setting.

Between 9th March and 30th April 2020, a total of 1,510 employees were tested for SARS-1

CoV-2 infection. 1,185 employees took advantage of the low-threshold testing facility. One 2 percent (n=11) were tested positive for SARS-CoV-2 infection, 18% being asymptomatic, 36% 3 showing mild and 36% moderate/severe symptoms (missing 10%). Furthermore, of 56 4 employees returning from SARS-CoV-2 risk regions, 18% (10/56) were tested SARS-CoV-2 5 positive. After risk contact tracking by the hospital infection control 6 patient-to-employee 6 transmissions were identified in 163 employees with contact to 55 SARS-CoV-2 positive 7 patients. 8 9

In the absence of easily accessible public SARS-CoV-2 testing facilities low-threshold SARS-11

CoV-2 testing facilities in hospitals with rapid testing resources help to identify SARS-CoV-2 12 The aim of this study was to evaluate, whether offering a free, voluntary low-threshold 10 testing for all hospital staff may help to manage SARS-CoV-2 infections in medical 11 institutions and prevent subsequent virus outbreaks. 12 13 Methods: 14

In the absence of an easily accessible public SARS-CoV-2 testing facility a low-threshold 15 testing facility was started at the University Hospital Bonn, Germany, on 9th March 2020. All 16 persons employed by the University Hospital Bonn got the opportunity of voluntary and free 17 SARS-CoV-2 testing using pharyngeal swabs irrespective of current clinical symptoms. Mild 18 symptoms were defined as sore throat, fatigue, and light cough, moderate/severe symptoms 19 as fever, severe cough, loss of smell/taste and myalgia. Employees with clinical symptoms 20 (mild and moderate/severe) received a doctor's note and could not return back to work 21 before they were tested negative for SARS-CoV-2. SARS-CoV-2 testing was also provided for 22 employees returning from regions declared as SARS-CoV-2 risk regions by the German 23 federal government agency and research institute responsible for disease control and 24 J o u r n a l P r e -p r o o f 5 prevention in Germany (Robert Koch Institute (RKI), Berlin, Germany), either during their 1 stay or shortly after their return (www.rki.de/covid-19-risikogebiete). The RKI continuously 2 updated information on SARS-CoV-2 risk regions, which were regularly implemented on the 3 University Hospital internal website. Furthermore, employees received SARS-CoV-2 testing 4 after risk contacts with SARS-CoV-2 positive patients or colleagues identified by the hospital 5 infection control irrespective of clinical symptoms. Risk assessment after SARS-CoV-2 contact 6 was conducted by the hospital infection control applying equally for employee-to-employee 7 and patient-to-employee risk contact. Employees were categorized according to type and 8 time of exposure to COVID-19 contact depending on personal protective equipment and 9

were informed personally by the hospital infection control if there was any risk of SARS-CoV-10 2 infection when applying the current RKI risk contact definitions. Importantly, in close 11 cooperation with the Institute of Virology of the University Bonn, test results were available 12 within 24 hours after sampling. 13

Employees after return from SARS-CoV-2 risk regions or with private or clinical SARS-CoV-2 14 risk contacts stayed in domestic quarantine for 14 days. Only when there was staffing 15

shortage critical for the hospital infrastructure employees were allowed to return back to 16 work after one negative test, being asymptomatic, wearing a mask, leading a 7-day 17 temperature log and repeating the test after 7 days. Serial examinations were carried out in 18 SARS-CoV-2 positive employees, who could return back to work after 2 negative SARS-CoV-2 19 tests in order to minimize the risk of false-negative results. A similar approach was chosen 20 for COVID-19 patients, who stayed in isolation until 2 negative SARS-CoV-2 results were 21 obtained. 22

Employees were categorized according to their profession as group I with direct contact to 23 patients, e.g. nurses, doctors, allied health professionals, porters etc., group II with a non-24 J o u r n a l P r e -p r o o f 6 patient facing profession but potentially at higher risk of nosocomial exposure, e.g. domestic 1 and laboratory staff, group III working non-clinical, e.g. jobs in the hospital administration 2 and information technology, secretarial jobs etc. (Hunter et al., 2020) . Irrespective of their 3 profession group IV was defined as employees returning from high risk regions according to 4 the guidelines of the RKI. 5

This study was approved by the local ethics committee (No. 188/20). The low-threshold facility was used by 1,185 employees, the majority of whom belonged to 20 group I with direct patient contact (66%). Only 21% belonged to group II with a non-patient 21 facing profession and 12% to group III, who worked non-clinical (missing for n=15). They 22 received a SARS-CoV-2 test without having symptoms in 36% (n=425), experiencing mild 23 J o u r n a l P r e -p r o o f 7 symptoms in 44% (n=515), suffering of moderate/severe symptoms in 7% (n=77) (missing in 1 14% (n=168)). 2

Out of these 1,185 employees 11 (1%) were tested positive for SARS-CoV-2. Sixty-four 3 percent (n=7) were women and the median age was 32 (IQR 31;46). The majority of the 11 4 SARS-CoV-2 positive employees belonged to group I (n=7) having direct contact to patients, 5 only one was assigned to group II and 3 to group III. Importantly, 54% had no (n=2) or mild 6 (n=4) symptoms, while 36% (n=4) had moderate/severe symptoms (information missing in 7 n=1). 8

In 9 of these 11 SARS-CoV-2 positive tested individuals 133 risk contact persons were 9 identified by the hospital infection control. One employee-to-employee transmission was 10 diagnosed by the contact tracing, however no further transmission was found in the 11 subsequent 9 identified risk contacts. The remaining 2 (2/11) SARS-CoV-2 positive tested 12 employees had no risk contacts in hospital as they were away on leave. 13 14 Fifty-six (0.8%) of all employees were tested as returning travelers from regions declared as 15 SARS-CoV-2 risk regions by the RKI. As it was skiing season in Europe individuals mostly 16 returned from Austria (n=33). As many as 18% (10/56) of these individuals tested positive for 17 SARS-CoV-2 returning from Austria (n=8), Spain (n=1) and Switzerland (n=1), the majority 18 (90%) of them belonging to group I with direct contact to patients. Two employees had 19 already returned back to work, when the regions they had returned from were announced 20 as SARS-CoV-2 risk region. The hospital infection control identified 40 contact persons from 21 the hospital staff, but no transmission was detected. In the beginning of the COVID-19 pandemic an easily accessible public SARS-CoV-2 testing 23 was not available. Thus, the low-threshold testing facility was introduced to provide a free 24 J o u r n a l P r e -p r o o f 9 and voluntary SARS-CoV-2 testing opportunity for the employees of the University Hospital 1 Bonn. Importantly, positive SARS-CoV-2 test results were not linked with mandatory leave. 2 Thus, as much as 16% of employees of the University Hospital Bonn were tested for SARS-3

CoV-2 infection in the observation period of 53 days. 4

Of these employees 1% were tested positive for SARS-CoV-2. This was 10 times higher 5 compared to the cumulative incidence of SARS-CoV-2 infections during this time period in 6 Bonn (199/100,000). Importantly, 64% of these employees had missing or mild symptoms, 7 strengthening the significance of a low-threshold SARS-CoV-2 testing facility in a hospital 8 setting. The high prevalence of SARS-CoV-2 positive individuals with missing or mild 9 symptoms has also been shown in previous studies (Streeck et al., 2020) . 10

Working in a medical institution during times of global pandemics threatening millions of 11 lives worldwide is not only physical but also mental stress for HCW (Ives et al., 2009 ). It has 12 been shown that besides professional experience also social support is desperately needed 13 to handle a pandemic situation in a medical institution (Holmes et al., 2020) . The majority 14 (80%) of the 1,185 employees taking advantage of the voluntary low-threshold testing 15 facility had missing or mild symptoms. Providing a test opportunity, where test results are 16 available within 24 hours not only supports HCW in fear of SARS-CoV-2 infection 17 psychologically, but also enables HCW to return back to work more rapidly in times of critical 18 human resource planning (Chowell and Mizumoto, 2020) . Our study has limitations. Clusters of employee-to-employee and patient-to-employee 4 transmission were defined after risk contact assessment by the hospital infection control. 5

Further genomic analysis of SARS-CoV-2, however, was not performed to directly confirm 6 these transmission clusters. 

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