24172901] 6. Li F. Receptor recognition and cross-species infections of SARS coronavirus. Antiviral research. 2013; 100:246–254.10.1016/j.antiviral.2013.08.014 [PubMed: 23994189] 7. Sheahan T, et al. Mechanisms of zoonotic severe acute respiratory syndrome coronavirus host range expansion in human airway epithelium. Journal of virology. 2008; 82:2274–2285.10.1128/JVI. 02041-07 [PubMed: 18094188] 8. Yoshikawa T, et al. Dynamic innate immune responses of human bronchial epithelial cells to severe acute respiratory syndrome-associated coronavirus infection. PloS one. 2010; 5:e8729.10.1371/ journal.pone.0008729 [PubMed: 20090954] 9. Qiu X, et al. Reversion of advanced Ebola virus disease in nonhuman primates with ZMapp. Nature. 201 Effects of human anti-spike protein receptor binding domain antibodies on severe acute respiratory syndrome coronavirus neutralization escape and fitness. Journal of virology. 2014; 88:13769–13780.10.1128/JVI.02232-14 [PubMed: 25231316] 12. Rockx B, et al. Escape from human monoclonal antibody neutralization affects in vitro and in vivo SARS-CoV-2 and COVID-19: The most important research questions Kit‑San Yuen1 , Zi ‑Wei Ye2 , Sin‑Yee Fung1 , Chi‑Ping Chan1 and Dong‑Yan Jin1* Abstract Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an ongoing global health emergency. Here we highlight nine most important research questions concerning virus transmission, asymptomatic and presymptomatic virus shedding, diagnosis, treatment, vaccine development, origin of virus and viral pathogenesis. Keywords: SARS-CoV-2, COVID-19, 2019 novel coronavirus (2019-nCoV), Novel coronavirus pneumonia (NCP) © The Author(s) 2020. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativeco mmons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver causes an ongoing outbreak of lower respiratory tract disease called novel coronavirus pneumonia (NCP) by the Chinese government initially. Te disease name was subsequently recommended as COVID-19 by the World Health Organization. Meanwhile, 2019-nCoV was renamed SARS-CoV-2 by the International Committee on Taxonomy of Viruses. As of February 24, 2020, more than 80,000 confrmed cases including more than 2,700 deaths have been reported worldwide, afecting at least 37 countries. Te WHO has declared this a global health emergency at the end of January 2020. Te epicenter of this ongoing outbreak is in the city of Wuhan in Hubei Province of central China and the Huanan seafood wholesale market was thought to be at least one of the places where SARS-CoV-2 from an unknown animal source might have crossed the species barrier to infect humans. A pioneering study conducted in the city of Shenzhen near Hong Kong by a group of clinicians and scientists from the University of Hong Kong has provided the frst concrete evidence for human-to-human transmission of SARS-CoV-2 [1]. Tis is an excellent example of how a high-quality clinical study can make a major diference in policy setting. Several important clinical features of COVID-19 have also been documented in this study. First, an attack rate of 83% within the family context is alarmingly high, indicating the high transmissibility of SARS-CoV-2. Second, the clinical manifestations of COVID-19 in this family range from mild to moderate, with more systematic symptoms and more severe radiological abnormalities seen in older patients. Generally, COVID-19 appears to be less severe than SARS. Tird, an asymptomatic child was found to have ground-glass opacities in his lung and SARS-CoV-2 RNA in his sputum sample. Tis fnding of asymptomatic virus shedding raises the possibility for transmission of SARS-CoV-2 from asymptomatic carriers to others, which is later confrmed by others [2]. Finally, the presentation of diarrhea in two young adults from the same family also suggests the possibility for gastrointestinal involvement in SARSCoV-2 infection and fecal–oral transmission. Te study has set the stage for the control and management of COVID-19 [1]. Te work was completed