This supplementary appendix provides additional information on the clinical characteristics of coronavirus disease 2019 (COVID-19) in China. The study was conducted by the China Medical Treatment Expert Group for COVID-19, including members such as Nan-shan Zhong, Lan-juan Li, and others. The methods section outlines the definitions of exposure to wildlife, pneumonia, shock, acute respiratory distress syndrome (ARDS), acute kidney injury, secondary bacterial or fungal infection, and acute heart failure. Exposure to wildlife was defined as close contact with wildlife animals or visiting wildlife markets within two weeks before the onset of respiratory symptoms. Pneumonia was diagnosed based on symptoms and clinical signs. ARDS and shock were defined according to WHO guidelines. Acute kidney injury was defined based on serum creatinine levels and urine output. Secondary infections were diagnosed based on clinical findings and positive pathogen cultures. Acute heart failure was defined by clinical symptoms and signs. The study assessed exposure history through patient self-reporting. Laboratory testing for SARS-CoV-2 involved RT-PCR using specific primers and probes. The testing protocol followed WHO guidelines. The cycle threshold (Ct) values were used to determine positive results. The appendix also includes tables and figures describing clinical characteristics of patients, comparisons between SARS-CoV-2 and other coronaviruses, and chest imaging findings in non-severe and severe cases. References are provided for the definitions and methods used.This supplementary appendix provides additional information on the clinical characteristics of coronavirus disease 2019 (COVID-19) in China. The study was conducted by the China Medical Treatment Expert Group for COVID-19, including members such as Nan-shan Zhong, Lan-juan Li, and others. The methods section outlines the definitions of exposure to wildlife, pneumonia, shock, acute respiratory distress syndrome (ARDS), acute kidney injury, secondary bacterial or fungal infection, and acute heart failure. Exposure to wildlife was defined as close contact with wildlife animals or visiting wildlife markets within two weeks before the onset of respiratory symptoms. Pneumonia was diagnosed based on symptoms and clinical signs. ARDS and shock were defined according to WHO guidelines. Acute kidney injury was defined based on serum creatinine levels and urine output. Secondary infections were diagnosed based on clinical findings and positive pathogen cultures. Acute heart failure was defined by clinical symptoms and signs. The study assessed exposure history through patient self-reporting. Laboratory testing for SARS-CoV-2 involved RT-PCR using specific primers and probes. The testing protocol followed WHO guidelines. The cycle threshold (Ct) values were used to determine positive results. The appendix also includes tables and figures describing clinical characteristics of patients, comparisons between SARS-CoV-2 and other coronaviruses, and chest imaging findings in non-severe and severe cases. References are provided for the definitions and methods used.