Inclusion Criteria:  Clinically or pathologically diagnosed with pre-existing liver disease, including: chronic liver disease, cirrhosis, liver cancer, liver transplant subjects, etc.; Receiving the whole-course COVID-19 vaccination for 14 days or more; Volunteer to participate in this study.  Exclusion Criteria:  Younger than 18 years old; Women during pregnancy or lactation; Research on other situations deemed unsuitable for selection.