key: cord-0901326-wg01nmjh
authors: Arimura, Ken; Tagaya, Etsuko; Kikuchi, Ken; Mitsuda, Toshihiro; Yasuda, Gaku; Azuma, Haruna; Konda, Naoko; Ikarashi, Yuichi; Chiba, Yukihide; Kusama, Kaoru; Sakama, Reiko; Hagiwara, Shotaro; Shimizu, Satoru; Shimamoto, Ken; Nomura, Minoru; Yaguchi, Arino; Niinami, Hiroshi; Kondo, Mitsuko; Tanabe, Kazunari; Kawana, Masatoshi
title: Polymerase-chain reaction testing to prevent hospital-acquired severe acute respiratory syndrome coronavirus 2 infection in Shinjuku, an epicenter in Tokyo: the Tokyo Women’s Medical University model
date: 2021-01-26
journal: Respir Investig
DOI: 10.1016/j.resinv.2020.12.009
sha: 618a60c22054f16495c4fc397174c3bb95411fa4
doc_id: 901326
cord_uid: wg01nmjh

Hospital-acquired severe acute respiratory virus coronavirus 2 (SARS-CoV-2) infection is a healthcare challenge. We hypothesized that polymerase chain reaction testing of symptomatic triaged outpatients and all inpatients before hospitalization in Shinjuku, a coronavirus disease 2019 (COVID-19) epicenter in Tokyo, using the Tokyo Women’s Medical University (TMWU) model would be feasible and efficient at preventing COVID-19. This retrospective study enrolled 2,981 patients from March to May 2020. The prevalence of SARS-CoV-2 infection was 1.81% (95% confidence interval [CI]: 0.95–3.47%) in triaged symptomatic outpatients, 0.04% (95% CI: 0.0002–0.2%) in scheduled asymptomatic inpatients, 3.78% (95% CI: 1.82–7.26 %) in emergency inpatients, and 2.4% (95% CI: 1.49–3.82%) in symptomatic patients. There were no cases of hospital-acquired SARS-CoV-2 infection. This shows that the TWMU model could prevent hospital-acquired SARS-CoV-2 infection and is feasible and effective in reducing the impact of SARS-CoV-2 infection in the hospitals.

Coronavirus disease 2019 (COVID-19) has spread rapidly worldwide [1] . As of September 14, 2020, a total of 28,637,952 cases have been reported worldwide, including 917,417 deaths [2] . Patients with hospital-acquired infections may increase the mortality rates [3] because they often have comorbidities such as cardiovascular disease, cancer, diabetes mellitus, and chronic obstructive pulmonary disease, which worsen the prognosis of COVID-19 [4] . In addition, COVID-19 can cause healthcare systems to collapse during the pandemic. Patients with asymptomatic severe acute respiratory virus syndrome coronavirus 2 (SARS-CoV-2) infection and emergency inpatients with COVID-19 are sources of hospital-acquired SARS-CoV-2 infection [5] .

These patients play an important role in SARS-CoV-2 transmission [6] . To prevent this hospital-acquired infection, we hypothesized that polymerase chain reaction (PCR) testing for SARS-CoV-2 in triaged outpatients and all inpatients may be feasible and efficient, and it may reveal the prevalence of COVID-19 with other comorbidities in the Shinjuku area, an epicenter in Tokyo during the first wave of the COVID-19 epidemic.

The purpose of this study was to assess the effectiveness of PCR testing for 

A total of 2,981 patients were enrolled in this retrospective study from March to May 2020 at TWMU Hospital using data retrieved from the patients' medical records.

Informed consent was obtained from all the patients before PCR testing. Patients who refused PCR testing were excluded.

Patients aged over 18 years were eligible and were divided into four groups. The first group comprised triaged outpatients with any symptoms suggestive of COVID-19, such as fever, cough, sore throat, dyspnea, dullness, chills, muscle pain, nausea, vomiting, diarrhea, and loss of taste and smell. The second group comprised scheduled asymptomatic inpatients hospitalized for a disease other than COVID-19. These patients were tested for SARS-CoV-2 using PCR within 7 days before hospitalization. The third group comprised emergency inpatients with problems such as pneumonia, bleeding, myocardial infarction, or heart failure. The fourth group comprised a combination of the symptomatic triaged outpatients and the emergency inpatients in the first and third groups, respectively. Inpatients with COVID-19 symptoms, such as fever or pneumonia, before hospitalization were hospitalized in a private room with/without a depressurized device. Because the probability of a false-negative PCR test result decreases to 20%, 8 days after exposure or 3 days after symptom onset [7] , inpatients were scheduled to J o u r n a l P r e -p r o o f undergo up to 3 PCR tests, depending on their computed tomography imaging results.

Patients were quarantined according to their PCR test results.

We defined the TWMU model as systematic PCR testing of triaged outpatients and all inpatients on admission to the hospital, and the retesting of inpatients after admission, as described above. The study was approved by the Institutional Review Board of TWMU Hospital (approval number: 5,649), the board disclosed the study on the hospital website.

Samples were collected from patients' nasal cavities with a swab (503CS01-E, BP100; Shin Corporation, Hyogo, Japan). Viral RNA was extracted using QIAamp Viral Data analysis was carried out using Statistical Analysis System (SAS Institute Inc., Cary, NC, USA). The standard deviation (SD) and 95% credible interval (CI) were used to compare the SARS-CoV-2 prevalence between groups.

A total of 2,981 patients were eligible for this study, including 442 symptomatic triaged Table 1 . After testing positive, those patients were quarantined at home or in the hospital for treatment, according to their symptom severity. As of September 14, 2020, our hospital had no hospital-acquired SARS-CoV-2 infections using the TWMU model.

In this study, we assessed the effectiveness of PCR testing for SARS-CoV-2 to prevent hospital-acquired infection. The prevalence of infection among asymptomatic triaged patients and emergency inpatients was higher than that of scheduled asymptomatic inpatients, although the overall prevalence during this period was low.

In Japan there has been debate about whether the small number of patients diagnosed with COVID-19 was due to the limited testing. Some studies have found that 57-75% of individuals with SARS-CoV-2 infection are asymptomatic [8, 9] . In our study, the J o u r n a l P r e -p r o o f prevalence of SARS-CoV-2 infection in asymptomatic patients with other diseases before scheduled hospitalization was 0.04%, which is relatively low compared to that of Western countries [8, 9] This study had several limitations. First, it was conducted in a single institution retrospectively and did not apply a randomized controlled design to validate the results.

Second, it was conducted only at the epicenter in Tokyo, and the situation might be different in other epicenters in the world. Third, implementing this model is costly and it takes time to confirm the PCR result. Less costly rapid tests need to be developed.

The prevalence of SARS-CoV-2 infection in symptomatic patients, including triaged outpatients and emergency inpatients with other diseases, was higher than that of J o u r n a l P r e -p r o o f asymptomatic patients undergoing scheduled hospitalization for other diseases. There were no hospital-acquired SARS-CoV-2 infections in our hospital. Therefore, the TWMU model is feasible and effective for preventing hospital-acquired SARS-CoV-2 infection. Abbreviations: CI, credible interval; no., number; SD, standard deviation, J o u r n a l P r e -p r o o f

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The authors thank Hitomi Miura, Kazuko Shiraishi, Ritsuko Iwamoto, Yoshiko Kondo, Tomoko Uchida, Kaori Ideguchi, Naoko Zama, and Noriko Mishima for their assistance.

The authors have no conflicts of interest. 

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