key: cord-0763154-klgea1k7
authors: Farfour, E.; Ballester, M.-C.; Lecuru, M.; Verrat, A.; Imhaus, E.; Mellot, F.; Karnycheff, F.; Vasse, M.; Cerf, C.; Lesprit, P.
title: COVID-19: before stopping specific infection control measures, be sure to exclude the diagnosis
date: 2020-04-25
journal: J Hosp Infect
DOI: 10.1016/j.jhin.2020.04.021
sha: 2b1873bd1b1720f5cc2629ec0c769d023a63f097
doc_id: 763154
cord_uid: klgea1k7

nan

Keywords: Sars-Cov-2; COVID-19; RT-PCR; chest computed tomography; Intervention and control prevention (IPC);

Dear Editor, Sars-Cov-2 raises the challenge of controlling the pandemic within the community but also preventing hospital transmission to medical staff and patients. Therefore, specific infection control measures are required. According to the French Health Authority recommendations, departments dedicated to Sars-Cov-2-infected patients (COVID-department) were implemented in our hospital.

As the clinical presentation of COVID-19 is non-specific, making a robust and accurate diagnosis is mandatory. According to the ECDC, laboratory confirmation is required for suspicious cases. Molecular methods performed on respiratory samples are considered as the gold standard, and i

Indeed, viral excretion appears early at the beginning of symptoms [1] . However, results turnaround times for RT-PCR often exceed 24 hours, and laborsatory diagnosis if threated in some countries by shortages of reagents [2] . In contrast, cessation of scheduled medical activities has made computed tomography rapidly available. Although chest computed tomography (CT) might be non-specific, in the context of the pandemic, it has been proposed as an alternative to RT-PCR for the early diagnosis confirmation of COVID-19 [3] .

We 

These findings emphasize: i) the need for applying rigorously standard precaution in all patients with respiratory symptoms; ii) organizing hospital with specific departments for COVIDpatients, non-COVID patients and a pre-admission zone for suspected patients while waiting for the diagnosis; iii) COVID-suspect patients should not be transferred until a final robust diagnosis; iv) the need for more rapid results turnaround times for RT-PCR than is currently available in many settings.

Although RT-PCR is considered the gold standard for the confirmation of COVID-19 diagnosis, false-negative results have been reported [3] [4] [5] . Although chest CT is known to be negative during the first days after onset of symptoms, CT was proposed for prompt diagnosis in case of respiratory symptoms [3] . However, in these studies, RT-PCR was mainly performed on throat swabs, which probably display a lower sensitivity [6] . Indeed, while the optimal sample is not defined for Sars-Cov-2 RT-PCR, nasopharyngeal swabs are more sensitive for influenza viruses [7] . Furthermore, all these studies included RT-PCR designed at the beginning of the pandemic when few viral genomes were already sequenced. Currently, according to WHO recommendations, at least two viral targets should be amplified [8] .

In the context of the pandemic, patients with COVID-19 should be admitted to specific wards.

Patients are held in a pre-admission zone until it is determined where a patient should be hospitalized. Our cases highlight significant difficulties in COVID-19 diagnosis. Microbiological and radiological exams are probably complementary, but both have limitations, and the final diagnosis should be made by clinical assessment in conjunction with a testing strategy. Rapid and accurate molecular methods are urgently needed for this purpose.

The authors state they have no conflict of interest to declare.

Viral load of SARS-CoV-2 in clinical samples

CT screening for early diagnosis of SARS-CoV-2 infection -Authors' reply

Correlation of Chest CT and RT-PCR Testing in Coronavirus Disease 2019 (COVID-19) in China: A Report of 1014 Cases

False-Negative Results of Real-Time Reverse-Transcriptase Polymerase Chain Reaction for Severe Acute Respiratory Syndrome Coronavirus 2: Role of Deep-Learning-Based CT Diagnosis and Insights from Two Cases

Detection of SARS-CoV-2 in Different Types of Clinical Specimens

Experience of different upper respiratory tract sampling strategies for detection of COVID-19

Comparison of respiratory specimen collection methods for detection of influenza virus infection by reverse transcription-PCR: A literature review

World Health Organization. Laboratory testing for 2019 novel coronavirus (2019-nCoV) in suspected human cases 2020

We thank all the teams at Foch Hospital involved in the care of COVID and non-COVID patients.

None.