1. Aged between 18 and 75 years, 2. In accordance with NCP criteria for severe and critical illness. Combined with the following epidemiological history, clinical manifestations, and pathogenic examinations to make a comprehensive judgment, 3. Will not participate in other drug clinical trials since the first day of Ulinastatin Injection admission, 4. Will sign written informed consent. Adolescents or patients who cannot sign informed consent must obtain informed consent from the guardian.

1. Aged between 18 and 75 years, 2. In accordance with NCP criteria for severe and critical illness. Combined with the following epidemiological history, clinical manifestations, and pathogenic examinations to make a comprehensive judgment, 3. Will not participate in other drug clinical trials since the first day of Ulinastatin Injection admission, 4. Will sign written informed consent. Adolescents or patients who cannot sign informed consent must obtain informed consent from the guardian.