Inclusion Criteria:  Age ≥18; Residents who are vaccinated with COVID-19 vaccines at Xidian Passenger Station from August 18th to September 20th, 2021; Able to understand the content of leaflets and questionnaires, and willing to participate in the study.  Exclusion Criteria:  Residents who are unable to get vaccinated with COVID-19 vaccines; Unable to understand the content of leaflets and questionnaires, or unwilling to participate in the study; Unreturned or incomplete questionnaires.