Articles Evidence before this study 27(66%)of 41 patients had a history of direct exposure to the 90e ectionsthat have emerged inthe past two decadesare All patients had pneumonia.A third of patients wer Dc): dt nfected with 2019-nCov kev lications of all the available evidence acute respiratory distres identified Added value of this study adetoknow the le spectrum and pa e enide eary an atmer to have 2 19-nCoV infection,and t spiratory.blood and non-IC patients.We hope tory of Systems Bio ogy of Chinal.A novel coronavirus which was named 2019-nco Methods Patients after 41 patients wer 2019-nCoV ine vith 201- of exposure to Huanan ood market across th generation se cing or ealtime RT-PCRm ised and the se Meanwhile,59 suspecte CTTGCAC CGTGGT-3:rev spital starting from Dec31.201 A C-3'BHQI ment oficials was soon formed after the ions included a the diag of pneumonia o hemical test(including caus I an fur creatine kinase,lactat common bac caus asal and pha tions in the desi tan tal (Wuhan. China).and fittested N95 mask parain avirus.SARS-Co edures w aken.This study w ved by China tion: nal and fungal examina e also pertormed Jin Yin-tan consent was waived by the Ehic es during the influen ntibiotics rally an infcctious diseases. e designated hospital for emerging 9 Articles 498 www.thelancet.com Vol 395 February 15, 2020 of Pulmonary and Critical Care Medicine, The Central Hospital of Wuhan (Y Hu MD, W Yin MD), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Tsinghua University School of Medicine, Beijing, China (J Xu MDc); Department of Respiratory medicine, Zhongnan Hospital of Wuhan University, Wuhan, China (Prof Z Cheng MD); Department of Pulmonary and Critical Care Medicine, Peking University First Hospital, Beijing, China (Prof G Wang MD); Department of Pulmonary and Critical Care Medicine, Peking University People’s Hospital, Beijing, China (Prof Z Gao MD); and Tsinghua University-Peking University Joint Center for Life Sciences, Beijing, China (Prof B Cao) Correspondence to: Prof Bin Cao, Department of Pulmonary and Critical Care Medicine, China-Japan Friendship Hospital, Beijing 100029, China caobin_ben@163.com or Prof Jianwei Wang, NHC Key Laboratory of Systems Biology of Pathogens and Christophe Merieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China wangjw28@163.com We aim to describe epidemiological, clinical, laboratory, and radiological characteristics, treatment, and outcomes of patients confirmed to have 2019-nCoV infection, and to compare the clinical features between intensive care unit (ICU) and non-ICU patients. We hope our study findings will inform the global community of the emergence of this novel coronavirus and its clinical features. Methods Patients Following the pneumonia cases of unknown cause reported in Wuhan and considering the shared history of exposure to Huanan seafood market across the patients, an epidemiological alert was released by the local health authority on Dec 31, 2019, and the market was shut down on Jan 1, 2020. Meanwhile, 59 suspected cases with fever and dry cough were transferred to a designated hospital starting from Dec 31, 2019. An expert team of physicians, epidemiologists, virologists, and government officials was soon formed after the alert. Since the cause was unknown at the onset of these emerging infections, the diagnosis of pneumonia of unknown cause in Wuhan was based on clinical characteristics, chest imaging, and the ruling out of common bacterial and viral pathogens that cause pneumonia. Suspected patients were isolated using airborne precautions in the designated hospital, Jin Yin￾tan Hospital (Wuhan, China), and fit-tested N95 masks and airborne precautions for aerosol-generating procedures were taken. This study was approved by the National Health Commission of China and Ethics Commission of Jin Yin-tan Hospital (KY-2020-01.01). Written informed consent was waived by the Ethics Commission of the designated hospital for emerging infectious diseases. Procedures Local centres for disease control and prevention collected respiratory, blood, and faeces specimens, then shipped them to designated authoritative laboratories to detect the pathogen (NHC Key Laboratory of Systems Biology of Pathogens and Christophe Mérieux Laboratory, Beijing, China). A novel coronavirus, which was named 2019-nCoV, was isolated then from lower respiratory tract specimen and a diagnostic test for this virus was developed soon after that.14 Of 59 suspected cases, 41 patients were confirmed to be infected with 2019-nCoV. The presence of 2019-nCoV in respiratory specimens was detected by next￾generation sequencing or real-time RT-PCR methods. The primers and probe target to envelope gene of CoV were used and the sequences were as follows: forward primer 5′-ACTTCTTTTTCTTGCTTTCGTGGT-3′; reverse primer 5′-GCAGCAGTACGCACACAATC-3′; and the probe 5′CY5-CTAGTTACACTAGCCATCCTTACTGC-3′BHQ1. Conditions for the amplifications were 50°C for 15 min, 95°C for 3 min, followed by 45 cycles of 95°C for 15 s and 60°C for 30 s. Initial investigations included a complete blood count, coagulation profile, and serum biochemical test (including renal and liver function, creatine kinase, lactate dehydro￾genase, and electrolytes). Respiratory specimens, including nasal and pharyngeal swabs, bronchoalveolar lavage fluid, sputum, or bronchial aspirates were tested for common viruses, including influenza, avian influenza, respiratory syncytial virus, adenovirus, parainfluenza virus, SARS-CoV and MERS-CoV using real-time RT-PCR assays approved by the China Food and Drug Administration. Routine bacterial and fungal examinations were also performed. Given the emergence of the 2019-nCoV pneumonia cases during the influenza season, antibiotics (orally and intravenously) and oseltamivir (orally 75 mg twice daily) were empirically administered. Corticosteroid therapy Research in context Evidence before this study Human coronaviruses, including hCoV-229E, OC43, NL63, and HKU1, cause mild respiratory diseases. Fatal coronavirus infections that have emerged in the past two decades are severe acute respiratory syndrome coronavirus (SARS-CoV) and the Middle East respiratory syndrome coronavirus. We searched PubMed and the China National Knowledge Infrastructure database for articles published up to Jan 11, 2020, using the keywords “novel coronovirus”, “2019 novel coronavirus”, or “2019-nCoV”. No published work about the human infection caused by the 2019 novel coronavirus (2019-nCoV) could be identified. Added value of this study We report the epidemiological, clinical, laboratory, and radiological characteristics, treatment, and clinical outcomes of 41 laboratory-confirmed cases infected with 2019-nCoV. 27 (66%) of 41 patients had a history of direct exposure to the Huanan seafood market. The median age of patients was 49·0 years (IQR 41·0–58·0), and 13 (32%) patients had underlying disease. All patients had pneumonia. A third of patients were admitted to intensive care units, and six died. High concentrations of cytokines were recorded in plasma of critically ill patients infected with 2019-nCoV. Implications of all the available evidence 2019-nCoV caused clusters of fatal pneumonia with clinical presentation greatly resembling SARS-CoV. Patients infected with 2019-nCoV might develop acute respiratory distress syndrome, have a high likelihood of admission to intensive care, and might die. The cytokine storm could be associated with disease severity. More efforts should be made to know the whole spectrum and pathophysiology of the new disease