 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. This article was authored by Kit Sen Yuan, Xi, Wei Yi, Xin Yi Fun and others.