Subject can be excluded by any of the following: 1.COVID-19 antibody test is positive, 2.Those with confirmed infection of SARS or MERS virus previously. 3.Those with an acute infection within 2 weeks before vaccination. 4.Those with a history of needle sickness. 5.Those with a metal implant within 20 cm from the planned injection site. 6.Those with a tattoo, keloid formation or hypertrophic scar at the planned injection site. 7.Those implanted with cardiac pacemaker or automatic implantable cardioverter defibrillator (AICD). 8.Those with any pre-excitation syndrome or relevant history, e.g. Wolff-Parkinson-White syndrome. 9.Female subjects with a positive result of urine pregnancy test, pregnant/lactating women, or women planning to be pregnant within 12 months (for women of childbearing potential aged < 60 years old). 10.Those undergoing organ transplantation or bone marrow transplantation recipients due to diseases that may cause immunodeficiency or immunosuppression, e.g. congenital immunodeficiency and malignant blood tumors (leukemia and lymphoma). 11.Those with allergic disease or allergic constitution (e.g. with history of angioedema/neuroedema or urticaria). 12.Those with a history of serious allergic reaction to any previous vaccination or are known to be allergic to this product or its preparation components (e.g. DNA plasmid and sodium citrate). 13.Those who previously suffered or currently suffer from clinically significant cardiovascular (except hypertension that can be controlled by drugs), respiratory, hepatic (except mild fatty liver), renal, gastrointestinal (except chronic gastritis), endocrine, hematological or nervous system diseases that may affect the study evaluation as assessed by the investigators, or cause risks during the vaccination of the investigational vaccine, or interfere with the interpretation of data. Examples of excluded conditions include but are not limited to: coronary heart disease, angina pectoris, heart failure, cardiomyopathy, chronic obstructive pulmonary emphysema, pulmonary fibrosis, asthma, hepatitis, cirrhosis, renal impairment, diabetes mellitus, anemia, cerebrovascular disease, epilepsy, schizophrenia, etc. 14.Those with psychiatric history. 15.Those who have undergone surgery or chemotherapy within 4 weeks before inoculation of the investigational vaccine, or who plan to undergo a surgery during the study period. 16.Those who have received blood products (e.g., immunoglobulin), investigational drugs/devices within the 12 weeks before inoculation of the investigational vaccine, or plan to use them during the study period. 17.Those who have received another vaccine within 4 weeks before inoculation of the investigational vaccine. 18.Those with immunosuppression effects caused by drug use, including: Long-term use (>= 7 days) of oral or parenteral glucocorticoids (excluding topical corticosteroids, and/or corticosteroids containing eye drops, low-dose methotrexate, or corticosteroids with a dose less than 20 mg/day), Those who are using or are expected to use antirheumatic drugs (e.g. azathioprine, cyclophosphamide, cyclosporin, and methotrexate) and biological drugs for disease alleviation, e.g. TNF-a inhibitors (e.g., infliximab, adalimumab, or etanercept), Those with other immunosuppression effects of clinical significance that may affect the safety of subjects, interfere with the study assessment or endpoint evaluation, or otherwise affect the validity of the stu

Subject can be excluded by any of the following: 1.COVID-19 antibody test is positive, 2.Those with confirmed infection of SARS or MERS virus previously. 3.Those with an acute infection within 2 weeks before vaccination. 4.Those with a history of needle sickness. 5.Those with a metal implant within 20 cm from the planned injection site. 6.Those with a tattoo, keloid formation or hypertrophic scar at the planned injection site. 7.Those implanted with cardiac pacemaker or automatic implantable cardioverter defibrillator (AICD). 8.Those with any pre-excitation syndrome or relevant history, e.g. Wolff-Parkinson-White syndrome. 9.Female subjects with a positive result of urine pregnancy test, pregnant/lactating women, or women planning to be pregnant within 12 months (for women of childbearing potential aged < 60 years old). 10.Those undergoing organ transplantation or bone marrow transplantation recipients due to diseases that may cause immunodeficiency or immunosuppression, e.g. congenital immunodeficiency and malignant blood tumors (leukemia and lymphoma). 11.Those with allergic disease or allergic constitution (e.g. with history of angioedema/neuroedema or urticaria). 12.Those with a history of serious allergic reaction to any previous vaccination or are known to be allergic to this product or its preparation components (e.g. DNA plasmid and sodium citrate). 13.Those who previously suffered or currently suffer from clinically significant cardiovascular (except hypertension that can be controlled by drugs), respiratory, hepatic (except mild fatty liver), renal, gastrointestinal (except chronic gastritis), endocrine, hematological or nervous system diseases that may affect the study evaluation as assessed by the investigators, or cause risks during the vaccination of the investigational vaccine, or interfere with the interpretation of data. Examples of excluded conditions include but are not limited to: coronary heart disease, angina pectoris, heart failure, cardiomyopathy, chronic obstructive pulmonary emphysema, pulmonary fibrosis, asthma, hepatitis, cirrhosis, renal impairment, diabetes mellitus, anemia, cerebrovascular disease, epilepsy, schizophrenia, etc. 14.Those with psychiatric history. 15.Those who have undergone surgery or chemotherapy within 4 weeks before inoculation of the investigational vaccine, or who plan to undergo a surgery during the study period. 16.Those who have received blood products (e.g., immunoglobulin), investigational drugs/devices within the 12 weeks before inoculation of the investigational vaccine, or plan to use them during the study period. 17.Those who have received another vaccine within 4 weeks before inoculation of the investigational vaccine. 18.Those with immunosuppression effects caused by drug use, including: Long-term use (>= 7 days) of oral or parenteral glucocorticoids (excluding topical corticosteroids, and/or corticosteroids containing eye drops, low-dose methotrexate, or corticosteroids with a dose less than 20 mg/day), Those who are using or are expected to use antirheumatic drugs (e.g. azathioprine, cyclophosphamide, cyclosporin, and methotrexate) and biological drugs for disease alleviation, e.g. TNF-a inhibitors (e.g., infliximab, adalimumab, or etanercept), Those with other immunosuppression effects of clinical significance that may affect the safety of subjects, interfere with the study assessment or endpoint evaluation, or otherwise affect the validity of the stu

The first segment: Subject can be excluded by any of the following: 1.COVID-19 antibody test is positive, 2.Those with confirmed infection of SARS or MERS virus previously. 3.Those with an acute infection within 2 weeks before vaccination. 4.Those with a history of needle sickness. 5.Those with a metal implant within 20 cm from the planned injection site. 6.Those with a tattoo, keloid formation or hypertrophic scar at the planned injection site. 7.Those implanted with cardiac pacemaker or automatic implantable cardioverter defibrillator (AICD). 8.Those with any pre-excitation syndrome or relevant history, e.g. Wolff-Parkinson-White syndrome. 9.Female subjects with a positive result of urine pregnancy test, pregnant/lactating women, or women planning to be pregnant within 12 months (for women of childbearing potential aged < 60 years old). 10.Those undergoing organ transplantation or bone marrow transplantation recipients due to diseases that may cause immunodeficiency or immunosuppression, e.g. congenital immunodeficiency and malignant blood tumors (leukemia and lymphoma). 11.Those with allergic disease or allergic constitution (e.g. with history of angioedema/neuroedema or urticaria). 12.Those with a history of serious allergic reaction to any previous vaccination or are known to be allergic to inactivated, DNA vaccines and their preparation components. 13.Those who previously suffered or currently suffer from clinically significant cardiovascular (except hypertension that can be controlled by drugs), respiratory, hepatic (except mild fatty liver), renal, gastrointestinal (except chronic gastritis), endocrine, hematological or nervous system diseases that may affect the study evaluation as assessed by the investigators, or cause risks during the vaccination of the investigational vaccine, or interfere with the interpretation of data. Examples of excluded conditions include but are not limited to: coronary heart disease, angina pectoris, heart failure, cardiomyopathy, chronic obstructive pulmonary emphysema, pulmonary fibrosis, asthma, hepatitis, cirrhosis, renal impairment, diabetes mellitus, anemia, cerebrovascular disease, epilepsy, schizophrenia, etc. 14.Those with psychiatric history. 15.Those who have undergone surgery or chemotherapy within 4 weeks before inoculation of the investigational vaccine, or who plan to undergo a surgery during the study period. 16.Those who have received blood products (e.g., immunoglobulin), investigational drugs/devices within the 12 weeks before inoculation of the investigational vaccine, or plan to use them during the study period. 17.Those who have received another vaccine within 4 weeks before inoculation of the investigational vaccine. 18.Those with immunosuppression effects caused by drug use, including: Long-term use (>= 7 days) of oral or parenteral glucocorticoids (excluding topical corticosteroids, and/or corticosteroids containing eye drops, low-dose methotrexate, or corticosteroids with a dose less than 20 mg/day), Those who are using or are expected to use antirheumatic drugs (e.g. azathioprine, cyclophosphamide, cyclosporin, and methotrexate) and biological drugs for disease alleviation, e.g. TNF-a inhibitors (e.g., infliximab, adalimumab, or etanercept), Those with other immunosuppression effects of clinical significance that may affect the safety of subjects, interfere with the study assessment or endpoint evaluation, or otherwise affect the validity of the study

The first segment: Subject can be excluded by any of the following: 1.COVID-19 antibody test is positive, 2.Those with confirmed infection of SARS or MERS virus previously. 3.Those with an acute infection within 2 weeks before vaccination. 4.Those with a history of needle sickness. 5.Those with a metal implant within 20 cm from the planned injection site. 6.Those with a tattoo, keloid formation or hypertrophic scar at the planned injection site. 7.Those implanted with cardiac pacemaker or automatic implantable cardioverter defibrillator (AICD). 8.Those with any pre-excitation syndrome or relevant history, e.g. Wolff-Parkinson-White syndrome. 9.Female subjects with a positive result of urine pregnancy test, pregnant/lactating women, or women planning to be pregnant within 12 months (for women of childbearing potential aged < 60 years old). 10.Those undergoing organ transplantation or bone marrow transplantation recipients due to diseases that may cause immunodeficiency or immunosuppression, e.g. congenital immunodeficiency and malignant blood tumors (leukemia and lymphoma). 11.Those with allergic disease or allergic constitution (e.g. with history of angioedema/neuroedema or urticaria). 12.Those with a history of serious allergic reaction to any previous vaccination or are known to be allergic to inactivated, DNA vaccines and their preparation components. 13.Those who previously suffered or currently suffer from clinically significant cardiovascular (except hypertension that can be controlled by drugs), respiratory, hepatic (except mild fatty liver), renal, gastrointestinal (except chronic gastritis), endocrine, hematological or nervous system diseases that may affect the study evaluation as assessed by the investigators, or cause risks during the vaccination of the investigational vaccine, or interfere with the interpretation of data. Examples of excluded conditions include but are not limited to: coronary heart disease, angina pectoris, heart failure, cardiomyopathy, chronic obstructive pulmonary emphysema, pulmonary fibrosis, asthma, hepatitis, cirrhosis, renal impairment, diabetes mellitus, anemia, cerebrovascular disease, epilepsy, schizophrenia, etc. 14.Those with psychiatric history. 15.Those who have undergone surgery or chemotherapy within 4 weeks before inoculation of the investigational vaccine, or who plan to undergo a surgery during the study period. 16.Those who have received blood products (e.g., immunoglobulin), investigational drugs/devices within the 12 weeks before inoculation of the investigational vaccine, or plan to use them during the study period. 17.Those who have received another vaccine within 4 weeks before inoculation of the investigational vaccine. 18.Those with immunosuppression effects caused by drug use, including: Long-term use (>= 7 days) of oral or parenteral glucocorticoids (excluding topical corticosteroids, and/or corticosteroids containing eye drops, low-dose methotrexate, or corticosteroids with a dose less than 20 mg/day), Those who are using or are expected to use antirheumatic drugs (e.g. azathioprine, cyclophosphamide, cyclosporin, and methotrexate) and biological drugs for disease alleviation, e.g. TNF-a inhibitors (e.g., infliximab, adalimumab, or etanercept), Those with other immunosuppression effects of clinical significance that may affect the safety of subjects, interfere with the study assessment or endpoint evaluation, or otherwise affect the validity of the study

1. Positive test result for SARS-CoV-2 (IgG and IgM) testing, 2. Those with confirmed infection with SARS or MERS virus previously, 3. Those with an acute infection within 2 weeks before vaccination, 4. Those with a history of needle sickness, 5. Those with a metal implant within 20 cm from the planned injection site, 6. Those with a tattoo, keloid formation or hypertrophic scar at the planned injection site, 7. Those implanted with cardiac pacemaker or automatic implantable cardioverter defibrillator (AICD), 8. Those with any pre-excitation syndrome or relevant history, e.g. Wolff-Parkinson-White syndrome, 9. Female subjects with a positive result of urine pregnancy test, pregnant/lactating women, or women planning to be pregnant within 12 months (for women of childbearing potential aged < 60 years old), 10. Those undergoing organ transplantation or bone marrow transplantation due to diseases that may cause immunodeficiency or immunosuppression, e.g. congenital immunodeficiency and malignant blood tumors (leukemia and lymphoma), 11. Those with allergic disease or allergic constitution (e.g. with history of angioedema/neuroedema or urticaria), 12. Those with a history of serious allergic reaction or known to be allergic to this product or components in its preparation (e.g. DNA plasmid and sodium citrate), 13. Those who previously suffered or currently suffer from clinically significant cardiovascular (except hypertension that can be controlled by drugs), respiratory, hepatic (except mild fatty liver), renal, gastrointestinal (except chronic gastritis), endocrine, hematological or nervous system diseases that may affect the study evaluation as assessed by the investigators, or cause risks during the vaccination of the investigational vaccine, or interfere with the interpretation of data. Examples of excluded conditions include but are not limited to: coronary heart disease, angina pectoris, heart failure, cardiomyopathy, chronic obstructive pulmonary emphysema, pulmonary fibrosis, asthma, hepatitis, cirrhosis, renal impairment, diabetes mellitus, anemia, cerebrovascular disease, epilepsy, schizophrenia, etc. [31], 14. Those with psychiatric history, 15. Those who have undergone surgery or chemotherapy within 4 weeks before inoculation of the investigational vaccine, or who plan to undergo a surgery during the study period, 16. Those who have received blood products (e.g., immunoglobulin), investigational drugs/devices within the 12 weeks before inoculation of the investigational vaccine, or plan to use them during the study period, 17. Those who have received another vaccine within 4 weeks before inoculation of the investigational vaccine, 18. Those with immunosuppression effects caused by drug use, including: (1) Long-term use (>=7 days) of oral or parenteral glucocorticoids (excluding topical corticosteroids, and/or corticosteroids containing eye drops, low-dose methotrexate, or corticosteroids with a dose less than 20 mg/day), (2) Those who are using or are expected to use antirheumatic drugs (e.g. azathioprine, cyclophosphamide, cyclosporin, and methotrexate) and biological drugs for disease alleviation, e.g. TNF-a inhibitors (e.g., infliximab, adalimumab, or etanercept), (3) Those with other immunosuppression effects of clinical significance that may affect the safety of subjects, interfere with the study assessment or endpoint evaluation, or otherwise affect the validity of the study results, 19. Those with hi

1. Positive test result for SARS-CoV-2 (IgG and IgM) testing, 2. Those with confirmed infection with SARS or MERS virus previously, 3. Those with an acute infection within 2 weeks before vaccination, 4. Those with a history of needle sickness, 5. Those with a metal implant within 20 cm from the planned injection site, 6. Those with a tattoo, keloid formation or hypertrophic scar at the planned injection site, 7. Those implanted with cardiac pacemaker or automatic implantable cardioverter defibrillator (AICD), 8. Those with any pre-excitation syndrome or relevant history, e.g. Wolff-Parkinson-White syndrome, 9. Female subjects with a positive result of urine pregnancy test, pregnant/lactating women, or women planning to be pregnant within 12 months (for women of childbearing potential aged < 60 years old), 10. Those undergoing organ transplantation or bone marrow transplantation due to diseases that may cause immunodeficiency or immunosuppression, e.g. congenital immunodeficiency and malignant blood tumors (leukemia and lymphoma), 11. Those with allergic disease or allergic constitution (e.g. with history of angioedema/neuroedema or urticaria), 12. Those with a history of serious allergic reaction or known to be allergic to this product or components in its preparation (e.g. DNA plasmid and sodium citrate), 13. Those who previously suffered or currently suffer from clinically significant cardiovascular (except hypertension that can be controlled by drugs), respiratory, hepatic (except mild fatty liver), renal, gastrointestinal (except chronic gastritis), endocrine, hematological or nervous system diseases that may affect the study evaluation as assessed by the investigators, or cause risks during the vaccination of the investigational vaccine, or interfere with the interpretation of data. Examples of excluded conditions include but are not limited to: coronary heart disease, angina pectoris, heart failure, cardiomyopathy, chronic obstructive pulmonary emphysema, pulmonary fibrosis, asthma, hepatitis, cirrhosis, renal impairment, diabetes mellitus, anemia, cerebrovascular disease, epilepsy, schizophrenia, etc. [31], 14. Those with psychiatric history, 15. Those who have undergone surgery or chemotherapy within 4 weeks before inoculation of the investigational vaccine, or who plan to undergo a surgery during the study period, 16. Those who have received blood products (e.g., immunoglobulin), investigational drugs/devices within the 12 weeks before inoculation of the investigational vaccine, or plan to use them during the study period, 17. Those who have received another vaccine within 4 weeks before inoculation of the investigational vaccine, 18. Those with immunosuppression effects caused by drug use, including: (1) Long-term use (>=7 days) of oral or parenteral glucocorticoids (excluding topical corticosteroids, and/or corticosteroids containing eye drops, low-dose methotrexate, or corticosteroids with a dose less than 20 mg/day), (2) Those who are using or are expected to use antirheumatic drugs (e.g. azathioprine, cyclophosphamide, cyclosporin, and methotrexate) and biological drugs for disease alleviation, e.g. TNF-a inhibitors (e.g., infliximab, adalimumab, or etanercept), (3) Those with other immunosuppression effects of clinical significance that may affect the safety of subjects, interfere with the study assessment or endpoint evaluation, or otherwise affect the validity of the study results, 19. Those with hi