Subjects who meet any of the following exclusion criteria may not be enrolled: 1. Subjects who do not meet the health standards as assessed through comprehensive physical examination, mainly including: (1) With abnormal and clinically significant vital signs (pulse rate under conscious state < 50 beats/min or > 100 beats/min, systolic blood pressure < 140 mmHg or diastolic blood pressure < 90 mmHg), (2) Body mass index (BMI) < 18 kg/m2 or > 30 kg/m2, (3) With laboratory values exceeding the upper or lower limit of normal reference range by 1.2 times during the screening time window and are adjudicated to be clinically significant by the investigators, 2. Women with positive pregnancy test (which may be exempt for women in menstrual phase or with amenorrhea for at least 1 year or who have medical records of surgical sterilization), or in lactation period, or who plan to conceive within 12 months from the screening period to completion of immunizations, males whose spouse plans to conceive, males or females who plan to donate sperm or eggs, 3. Subjects who have been diagnosed as confirmed or suspected cases of COVID-19 pneumonia, who have contact with confirmed or suspected cases of COVID-19 within 1 month before signing the informed consent form, or who have traveled abroad or in areas with high epidemic incidence, or who are infected with COVID-19 or are COVID-19 carriers: positive for serum anti-SARS-CoV-2 specific antibody, or positive for SARS-CoV-2 nucleic acid in throat swab specimens, 4. Positive results of etiological or serological tests for hepatitis B (HBV), hepatitis C (HCV), syphilis or HIV, 5. With prior history of human coronavirus infection or disease such as SARS and MERS, 6. Subjects who develop acute diseases or are in acute attack of chronic diseases within 2 weeks before the first dose of investigational vaccine, or who have fever (axillary temperature > 37.3 degree C) or upper respiratory tract infection within 7 days before the first dose of investigational vaccine, 7. With any history of serious side effects due to vaccines or drugs, such as allergy, urticaria, skin eczema, dyspnea, angioneurotic edema, etc. 8. Have received any vaccine within 1 month before the first dose of investigational vaccine, 9. Subjects who cannot tolerate venipuncture, or have a history of needle or blood phobia, 10. With inherited bleeding tendency or coagulation dysfunction, or have a history of thrombosis or hemorrhagic disease, and have abnormal findings of coagulation function related indicators, 11. Have been diagnosed with congenital or acquired immunodeficiency (e.g., HIV infection), 12. Asplenia, functional asplenia, or have had surgical removal of other important organs for any reason, 13. With prior abnormal clinical manifestations and serious diseases that preclude the subjects from participating in the study, including but not limited to disorders of nervous system, cardiovascular system, blood and lymphatic system, immune system, kidney, liver, gastrointestinal tract, respiratory system, metabolic and skeletal diseases and history of malignant tumors (excluding patients with history of well-controlled chronic disease, such as diabetes, hypertension, etc.), 14. Have undergone surgery within 3 months before signing the informed consent form, or plan to undergo surgery (including cosmetic, dental and oral surgery) during the trial or within 3 months after the end of the trial, 15. Have donated blood or blood

Subjects who meet any of the following exclusion criteria may not be enrolled: 1. Subjects who do not meet the health standards as assessed through comprehensive physical examination, mainly including: (1) With abnormal and clinically significant vital signs (pulse rate under conscious state < 50 beats/min or > 100 beats/min, systolic blood pressure < 140 mmHg or diastolic blood pressure < 90 mmHg), (2) Body mass index (BMI) < 18 kg/m2 or > 30 kg/m2, (3) With laboratory values exceeding the upper or lower limit of normal reference range by 1.2 times during the screening time window and are adjudicated to be clinically significant by the investigators, 2. Women with positive pregnancy test (which may be exempt for women in menstrual phase or with amenorrhea for at least 1 year or who have medical records of surgical sterilization), or in lactation period, or who plan to conceive within 12 months from the screening period to completion of immunizations, males whose spouse plans to conceive, males or females who plan to donate sperm or eggs, 3. Subjects who have been diagnosed as confirmed or suspected cases of COVID-19 pneumonia, who have contact with confirmed or suspected cases of COVID-19 within 1 month before signing the informed consent form, or who have traveled abroad or in areas with high epidemic incidence, or who are infected with COVID-19 or are COVID-19 carriers: positive for serum anti-SARS-CoV-2 specific antibody, or positive for SARS-CoV-2 nucleic acid in throat swab specimens, 4. Positive results of etiological or serological tests for hepatitis B (HBV), hepatitis C (HCV), syphilis or HIV, 5. With prior history of human coronavirus infection or disease such as SARS and MERS, 6. Subjects who develop acute diseases or are in acute attack of chronic diseases within 2 weeks before the first dose of investigational vaccine, or who have fever (axillary temperature > 37.3 degree C) or upper respiratory tract infection within 7 days before the first dose of investigational vaccine, 7. With any history of serious side effects due to vaccines or drugs, such as allergy, urticaria, skin eczema, dyspnea, angioneurotic edema, etc. 8. Have received any vaccine within 1 month before the first dose of investigational vaccine, 9. Subjects who cannot tolerate venipuncture, or have a history of needle or blood phobia, 10. With inherited bleeding tendency or coagulation dysfunction, or have a history of thrombosis or hemorrhagic disease, and have abnormal findings of coagulation function related indicators, 11. Have been diagnosed with congenital or acquired immunodeficiency (e.g., HIV infection), 12. Asplenia, functional asplenia, or have had surgical removal of other important organs for any reason, 13. With prior abnormal clinical manifestations and serious diseases that preclude the subjects from participating in the study, including but not limited to disorders of nervous system, cardiovascular system, blood and lymphatic system, immune system, kidney, liver, gastrointestinal tract, respiratory system, metabolic and skeletal diseases and history of malignant tumors (excluding patients with history of well-controlled chronic disease, such as diabetes, hypertension, etc.), 14. Have undergone surgery within 3 months before signing the informed consent form, or plan to undergo surgery (including cosmetic, dental and oral surgery) during the trial or within 3 months after the end of the trial, 15. Have donated blood or blood