The main characteristics of all included studies are listed in Table 3. There were four studies in hospital inpatients (Ai 2020a; Chen X 2020; Yang 2020d; Zhao 2020a), seven studies in hospital outpatients (Cheng 2020a; Liang 2020; Nobel 2020; Peng 2020a; Song 2020b; Sun 2020a; Yan 2020a), and four studies in emergency departments (Feng 2020a; Tolia 2020; Wee 2020; Zhu 2020b). The setting was not specified in one study (Rentsch 2020); in the 'Summary of findings' table, we classified this study setting as being hospital outpatient under the assumption that at that time in the pandemic (February 2020 to March 2020) tests were not commonly available outside hospital clinics. There were no studies conducted in community primary care services.