inclusion criteria: subjects included in this trial must meet all of the following inclusion criteria: 1. adults aged 18 and above (both males and females are required); 2. individuals who are able to understand the contents listed in the informed consent form and the procedure of this clinical trial; are able to sign the informed consent form voluntarily; 3. individuals who are able to communicate well with the investigator and has the ability to understand and comply with the requirements of the clinical trial; 4. individuals who are at risk of sars-cov-2 infection or are exposed to covid-19 due to regional, occupational, activity and environmental factors; 5. for female participants of childbearing potential, effective contraception should be used within 2 weeks prior to participation in this study and the pregnancy test results is required to be negative (those with amenorrhea of at least 1 year or surgical sterilization verified by medical records could be exempted from the pregnancy test). participants should voluntarily agree to continue using at least one effective methods of contraception for 12 months after complete series (effective methods include oral contraceptives, injectable or implantable contraceptives, sustained-release topical contraceptives, hormonal patches, intrauterine device, sterilization, abstinence, condoms (for males), diaphragms, cervical caps, etc.). 6. healthy individuals with verified medical history: individuals who are in a stable condition and whose current diseases will not worsen for at least 3 months prior to enrollment to this study.

inclusion criteria: subjects included in this trial must meet all of the following inclusion criteria: 1. adults aged 18 and above (both males and females are required); 2. individuals who are able to understand the contents listed in the informed consent form and the procedure of this clinical trial; are able to sign the informed consent form voluntarily; 3. individuals who are able to communicate well with the investigator and has the ability to understand and comply with the requirements of the clinical trial; 4. individuals who are at risk of sars-cov-2 infection or are exposed to covid-19 due to regional, occupational, activity and environmental factors; 5. for female participants of childbearing potential, effective contraception should be used within 2 weeks prior to participation in this study and the pregnancy test results is required to be negative (those with amenorrhea of at least 1 year or surgical sterilization verified by medical records could be exempted from the pregnancy test). participants should voluntarily agree to continue using at least one effective methods of contraception for 12 months after complete series (effective methods include oral contraceptives, injectable or implantable contraceptives, sustained-release topical contraceptives, hormonal patches, intrauterine device, sterilization, abstinence, condoms (for males), diaphragms, cervical caps, etc.). 6. healthy individuals with verified medical history: individuals who are in a stable condition and whose current diseases will not worsen for at least 3 months prior to enrollment to this study.

inclusion criteria: subjects included in this trial must meet all of the following inclusion criteria: adults aged 18 and above (both males and females are required); individuals who are able to understand the contents listed in the informed consent form and the procedure of this clinical trial; are able to sign the informed consent form voluntarily; individuals who are able to communicate well with the investigator and has the ability to understand and comply with the requirements of the clinical trial; individuals who are at risk of sars-cov-2 infection or are exposed to covid-19 due to regional, occupational, activity and environmental factors; for female participants of childbearing potential, effective contraception should be used within 2 weeks prior to participation in this study and the pregnancy test results is required to be negative (those with amenorrhea of at least 1 year or surgical sterilization verified by medical records could be exempted from the pregnancy test). participants should voluntarily agree to continue using at least one effective methods of contraception for 12 months after complete series (effective methods include oral contraceptives, injectable or implantable contraceptives, sustained-release topical contraceptives, hormonal patches, intrauterine device, sterilization, abstinence, condoms (for males), diaphragms, cervical caps, etc.). healthy individuals with verified medical history: individuals who are in a stable condition and whose current diseases will not worsen for at least 3 months prior to enrollment to this study.

inclusion criteria: subjects included in this trial must meet all of the following inclusion criteria: adults aged 18 and above (both males and females are required); individuals who are able to understand the contents listed in the informed consent form and the procedure of this clinical trial; are able to sign the informed consent form voluntarily; individuals who are able to communicate well with the investigator and has the ability to understand and comply with the requirements of the clinical trial; individuals who are at risk of sars-cov-2 infection or are exposed to covid-19 due to regional, occupational, activity and environmental factors; for female participants of childbearing potential, effective contraception should be used within 2 weeks prior to participation in this study and the pregnancy test results is required to be negative (those with amenorrhea of at least 1 year or surgical sterilization verified by medical records could be exempted from the pregnancy test). participants should voluntarily agree to continue using at least one effective methods of contraception for 12 months after complete series (effective methods include oral contraceptives, injectable or implantable contraceptives, sustained-release topical contraceptives, hormonal patches, intrauterine device, sterilization, abstinence, condoms (for males), diaphragms, cervical caps, etc.). healthy individuals with verified medical history: individuals who are in a stable condition and whose current diseases will not worsen for at least 3 months prior to enrollment to this study.

inclusion criteria: subjects included in this trial must meet all of the following inclusion criteria: 1. adults aged 18 and above (both males and females are required); 2. individuals who are able to understand the contents listed in the informed consent form and the procedure of this clinical trial; are able to sign the informed consent form voluntarily; 3. individuals who are able to communicate well with the investigator and has the ability to understand and comply with the requirements of the clinical trial; 4. individuals who are at risk of sars-cov-2 infection or are exposed to covid-19 due to regional, occupational, activity and environmental factors; 5. for female participants of childbearing potential, effective contraception should be used within 2 weeks prior to participation in this study and the pregnancy test results is required to be negative (those with amenorrhea of at least 1 year or surgical sterilization verified by medical records could be exempted from the pregnancy test). participants should voluntarily agree to continue using at least one effective methods of contraception for 12 months after complete series (effective methods include oral contraceptives, injectable or implantable contraceptives, sustained-release topical contraceptives, hormonal patches, intrauterine device, sterilization, abstinence, condoms (for males), diaphragms, cervical caps, etc.). 6. healthy individuals with verified medical history: individuals who are in a stable condition and whose current diseases will not worsen for at least 3 months prior to enrollment to this study.

inclusion criteria: subjects included in this trial must meet all of the following inclusion criteria: 1. adults aged 18 and above (both males and females are required); 2. individuals who are able to understand the contents listed in the informed consent form and the procedure of this clinical trial; are able to sign the informed consent form voluntarily; 3. individuals who are able to communicate well with the investigator and has the ability to understand and comply with the requirements of the clinical trial; 4. individuals who are at risk of sars-cov-2 infection or are exposed to covid-19 due to regional, occupational, activity and environmental factors; 5. for female participants of childbearing potential, effective contraception should be used within 2 weeks prior to participation in this study and the pregnancy test results is required to be negative (those with amenorrhea of at least 1 year or surgical sterilization verified by medical records could be exempted from the pregnancy test). participants should voluntarily agree to continue using at least one effective methods of contraception for 12 months after complete series (effective methods include oral contraceptives, injectable or implantable contraceptives, sustained-release topical contraceptives, hormonal patches, intrauterine device, sterilization, abstinence, condoms (for males), diaphragms, cervical caps, etc.). 6. healthy individuals with verified medical history: individuals who are in a stable condition and whose current diseases will not worsen for at least 3 months prior to enrollment to this study.