inclusion criteria: 1. participant is willing and able to give written informed consent for participation in the study. 2. male or female, aged 18 years or above and in good health as determined by study clinician. 3. female participants of childbearing potential must be willing to ensure that they or their partner use effective contraception from 1 month prior to first immunization continuously until 3months after boost immunization. 4. in the investigator's opinion, is able and willing to comply with all trial requirements. 5. subjects had completed the 2-dose series vaccination of covid-19 inactivated vaccine(sinopharm) at least 24 weeks with the completed the 2-dose series as the primary vaccination according to the product label.

inclusion criteria: 1. participant is willing and able to give written informed consent for participation in the study. 2. male or female, aged 18 years or above and in good health as determined by study clinician. 3. female participants of childbearing potential must be willing to ensure that they or their partner use effective contraception from 1 month prior to first immunization continuously until 3months after boost immunization. 4. in the investigator's opinion, is able and willing to comply with all trial requirements. 5. subjects had completed the 2-dose series vaccination of covid-19 inactivated vaccine(sinopharm) at least 24 weeks with the completed the 2-dose series as the primary vaccination according to the product label.

inclusion criteria: participant is willing and able to give written informed consent for participation in the study. male or female, aged 18 years or above and in good health as determined by study clinician. female participants of childbearing potential must be willing to ensure that they or their partner use effective contraception from 1 month prior to first immunization continuously until 3months after boost immunization. in the investigator's opinion, is able and willing to comply with all trial requirements. subjects had completed the 2-dose series vaccination of covid-19 inactivated vaccine(sinopharm) at least 24 weeks with the completed the 2-dose series as the primary vaccination according to the product label.

inclusion criteria: participant is willing and able to give written informed consent for participation in the study. male or female, aged 18 years or above and in good health as determined by study clinician. female participants of childbearing potential must be willing to ensure that they or their partner use effective contraception from 1 month prior to first immunization continuously until 3months after boost immunization. in the investigator's opinion, is able and willing to comply with all trial requirements. subjects had completed the 2-dose series vaccination of covid-19 inactivated vaccine(sinopharm) at least 24 weeks with the completed the 2-dose series as the primary vaccination according to the product label.