 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 9 most important research questions concerning virus transmission, asymptomatic and pre-symptomatic virus shedding, diagnosis, treatment, vaccine development, origin of virus and viral pathogenesis. This article was authored by Kit San Yuan, Zi Wei Yi, Xin Yi Feng and others.