2.1 Participants
We recruited patients with laboratory-confirmed COVID-19 who admitted to the designated hospitals in Qingdao from January 22 to February 14, 2020. The detection of SARS-CoV-2 and other respiratory pathogens for all patients were tested at the onset of COVID-19. Data were collected onto standardized forms through interviews of infected persons. Epidemiological, demographic, clinical, laboratory, treatment and prognosis data were extracted from the interview as well as field reports. All patients were diagnosed with COVID-19 according to New Coronavirus Pneumonia Diagnosis and Treatment Plan (NHCPRC, 2020a; NHCPRC, 2020b; NHCPRC, 2020c).
This study was approved by the Ethics Commission of Qingdao Municipal Center for Disease Control and Prevention (Qingdao CDC) and written informed consent was waived considering the emergency of infectious disease.