1. Severe patients diagnosed with novel coronavirus pneumonia (COVID-19), 2. Aged 35 years old to 74 years old, 3. Patients or authorized family members volunteered to participate in this study and signed informed consent. Note: Case definition: Severe NCP: Refer to the New Coronavirus Pneumonia Diagnosis and Treatment Plan (Fifth Edition) formulated by the National Health Commission.

1. Severe patients diagnosed with novel coronavirus pneumonia (COVID-19), 2. Aged 35 years old to 74 years old, 3. Patients or authorized family members volunteered to participate in this study and signed informed consent. Note: Case definition: Severe NCP: Refer to the New Coronavirus Pneumonia Diagnosis and Treatment Plan (Fifth Edition) formulated by the National Health Commission.