Methods
All adult patients hospitalized in a COVID-19 first-line hospital in Paris, France, from January 25th, 2020 to April 30th, 2020 were included. All patients were tested by systematic mPCR testing if they presented Influenza-like illness (ILI) symptoms, according to the eCDC definition, and required hospitalization. The two mPCR assays used during the study period, the QIAstat-Dx SARS-CoV-2 respiratory panel, Qiagen [8], and the BioFire FilmArray RP2+, BioMérieux [9] allow for detecting a wide range of viral and atypical bacterial respiratory targets, including influenza A and B, parainfluenza virus, rhinoviruses/enteroviruses, RSV, metapneumovirus, adenovirus, human coronaviruses (229E, HKU1, OC43, and NL63), Mycoplasma pneumoniae, and Bordetella pertussis. According to the French national definition, a specific SARS-CoV-2 RT-PCR for at-risk patients was performed, starting from March 10th, 2020, when systematic testing for SARS-CoV-2 infection began. During this period, three SARS-CoV-2 RT-PCR assays were used: the WHO recommended in-house RT-PCR assay, the RealStar® SARS-CoV-2 RT-PCR kit (Altona, Germany), and the Cobas® SARS-CoV-2 assay (Roche Diagnostics, USA). All these assays provided similar performance and limit of detection [10,11]. Demographic, clinical, and biological features were prospectively collected in the Emergency Department (ED) and retrospectively from the other units. Baseline characteristics within each group were summarized using appropriate descriptive statistics. The statistical analysis was performed using Stata15. The research was approved by the local ethic committee N° CER-2020-6.