- history of sars-cov-2 infection(laboratory confirmed); - have received three and more doses of inactivated sars-cov-2 vaccine; - severe adverse reactions, such as urticaria, dyspnea, and angioneurotic edema , occurred during the primary immunization; - autoimmune disease such as systemic lupus erythematosus or immunodeficiency / immunosuppression such as aids, post-transplant; - severe chronic diseases, severe cardiovascular diseases, hypertension and diabetes that cannot be controlled by drugs, liver or kidney diseases, malignant tumors, etc; - severe neurological disease (epilepsy, convulsions or convulsions) or mental illness; - diagnosed abnormal blood coagulation function (eg, lack of blood coagulation factors, blood coagulopathy, abnormal platelets) or obvious bruising or blood coagulation; - immunosuppressive therapy, cytotoxic therapy, inhaled corticosteroids(excluding allergic rhinitis corticosteroid spray therapy, acute noncomplicated dermatitis superficial corticosteroid therapy) in the past 6 months; - history of alcohol or drug abuse; - receipt of blood products within in the past 3 months; - receipt of other investigational drugs in the past 30 days; - receipt of attenuated live vaccines in the past 14 days; - acute diseases or acute exacerbation of chronic diseases within 7 days prior to booster vaccination; - axillary temperature >37.0°c; - already pregnant or are breastfeeding, planning to get pregnant within 1months (according to subjects' self-report and urine pregnancy test results); - participated in other clinical trials prior to enrollment and during the follow-up period, or planned to participate in other clinical trials during the clinical trial period; - according to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial.

- history of sars-cov-2 infection(laboratory confirmed); - have received three and more doses of inactivated sars-cov-2 vaccine; - severe adverse reactions, such as urticaria, dyspnea, and angioneurotic edema , occurred during the primary immunization; - autoimmune disease such as systemic lupus erythematosus or immunodeficiency / immunosuppression such as aids, post-transplant; - severe chronic diseases, severe cardiovascular diseases, hypertension and diabetes that cannot be controlled by drugs, liver or kidney diseases, malignant tumors, etc; - severe neurological disease (epilepsy, convulsions or convulsions) or mental illness; - diagnosed abnormal blood coagulation function (eg, lack of blood coagulation factors, blood coagulopathy, abnormal platelets) or obvious bruising or blood coagulation; - immunosuppressive therapy, cytotoxic therapy, inhaled corticosteroids(excluding allergic rhinitis corticosteroid spray therapy, acute noncomplicated dermatitis superficial corticosteroid therapy) in the past 6 months; - history of alcohol or drug abuse; - receipt of blood products within in the past 3 months; - receipt of other investigational drugs in the past 30 days; - receipt of attenuated live vaccines in the past 14 days; - acute diseases or acute exacerbation of chronic diseases within 7 days prior to booster vaccination; - axillary temperature >37.0°c; - already pregnant or are breastfeeding, planning to get pregnant within 1months (according to subjects' self-report and urine pregnancy test results); - participated in other clinical trials prior to enrollment and during the follow-up period, or planned to participate in other clinical trials during the clinical trial period; - according to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial.