* travel / residence history of wuhan city and surrounding areas or other communities with case reports within 14 days prior to the enrolment; * contact with sars-cov-2 infected persons (positive for nucleic acid detection) within 14 days prior to the enrolment; * contact patients with fever or respiratory symptoms from wuhan city and surrounding areas, or from communities with case reports within 14 days prior to the enrolment; * two or more cases of fever and / or respiratory symptoms in a small contact area of subjects, such as family, office, school class or other places within 14 days prior to the enrolment; * history of sars; * history of sars-cov-2 infection; * history of asthma, allergy to vaccines or vaccine ingredients, and serious adverse reactions to vaccines, such as urticaria, dyspnea, angioneuroedema; * congenital malformation or developmental disorder, genetic defect, severe malnutrition, etc; * autoimmune disease or immunodeficiency / immunosuppression; * serious chronic disease, serious cardiovascular disease, hypertension and diabetes that cannot be controlled by drugs, hepatorenal disease, malignant tumor, etc; * serious nervous system disease (epilepsy, convulsion or convulsion) or psychosis; * thyroid disease or history of thyroidectomy, asplenia, functional asplenia, asplenia or splenectomy resulting from any condition; * 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 non-complicated dermatitis superficial corticosteroid therapy) in the past 6 months; * long history of alcohol or drug abuse; * receipt of blood products 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; * receipt of inactivated or subunit vaccines in the past 7 days; * acute diseases or acute exacerbation of chronic diseases in the past 7 days; * axillary temperature \>37.0°c; * according to the investigator's judgment, the subject has any other factors that are not suitable for the clinical trial.

* travel / residence history of wuhan city and surrounding areas or other communities with case reports within 14 days prior to the enrolment; * contact with sars-cov-2 infected persons (positive for nucleic acid detection) within 14 days prior to the enrolment; * contact patients with fever or respiratory symptoms from wuhan city and surrounding areas, or from communities with case reports within 14 days prior to the enrolment; * two or more cases of fever and / or respiratory symptoms in a small contact area of subjects, such as family, office, school class or other places within 14 days prior to the enrolment; * history of sars; * history of sars-cov-2 infection; * history of asthma, allergy to vaccines or vaccine ingredients, and serious adverse reactions to vaccines, such as urticaria, dyspnea, angioneuroedema; * congenital malformation or developmental disorder, genetic defect, severe malnutrition, etc; * autoimmune disease or immunodeficiency / immunosuppression; * serious chronic disease, serious cardiovascular disease, hypertension and diabetes that cannot be controlled by drugs, hepatorenal disease, malignant tumor, etc; * serious nervous system disease (epilepsy, convulsion or convulsion) or psychosis; * thyroid disease or history of thyroidectomy, asplenia, functional asplenia, asplenia or splenectomy resulting from any condition; * 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 non-complicated dermatitis superficial corticosteroid therapy) in the past 6 months; * long history of alcohol or drug abuse; * receipt of blood products 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; * receipt of inactivated or subunit vaccines in the past 7 days; * acute diseases or acute exacerbation of chronic diseases in the past 7 days; * axillary temperature \>37.0°c; * according to the investigator's judgment, the subject has any other factors that are not suitable for the clinical trial.

- travel / residence history of wuhan city and surrounding areas or other communities with case reports within 14 days prior to the enrolment; - contact with sars-cov-2 infected persons (positive for nucleic acid detection) within 14 days prior to the enrolment; - contact patients with fever or respiratory symptoms from wuhan city and surrounding areas, or from communities with case reports within 14 days prior to the enrolment; - two or more cases of fever and / or respiratory symptoms in a small contact area of subjects, such as family, office, school class or other places within 14 days prior to the enrolment; - history of sars; - history of sars-cov-2 infection; - history of asthma, allergy to vaccines or vaccine ingredients, and serious adverse reactions to vaccines, such as urticaria, dyspnea, angioneuroedema; - congenital malformation or developmental disorder, genetic defect, severe malnutrition, etc; - autoimmune disease or immunodeficiency / immunosuppression; - serious chronic disease, serious cardiovascular disease, hypertension and diabetes that cannot be controlled by drugs, hepatorenal disease, malignant tumor, etc; - serious nervous system disease (epilepsy, convulsion or convulsion) or psychosis; - thyroid disease or history of thyroidectomy, asplenia, functional asplenia, asplenia or splenectomy resulting from any condition; - 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 non-complicated dermatitis superficial corticosteroid therapy) in the past 6 months; - long history of alcohol or drug abuse; - receipt of blood products 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; - receipt of inactivated or subunit vaccines in the past 7 days; - acute diseases or acute exacerbation of chronic diseases in the past 7 days; - axillary temperature >37.0°c; - according to the investigator's judgment, the subject has any other factors that are not suitable for the clinical trial.

- travel / residence history of wuhan city and surrounding areas or other communities with case reports within 14 days prior to the enrolment; - contact with sars-cov-2 infected persons (positive for nucleic acid detection) within 14 days prior to the enrolment; - contact patients with fever or respiratory symptoms from wuhan city and surrounding areas, or from communities with case reports within 14 days prior to the enrolment; - two or more cases of fever and / or respiratory symptoms in a small contact area of subjects, such as family, office, school class or other places within 14 days prior to the enrolment; - history of sars; - history of sars-cov-2 infection; - history of asthma, allergy to vaccines or vaccine ingredients, and serious adverse reactions to vaccines, such as urticaria, dyspnea, angioneuroedema; - congenital malformation or developmental disorder, genetic defect, severe malnutrition, etc; - autoimmune disease or immunodeficiency / immunosuppression; - serious chronic disease, serious cardiovascular disease, hypertension and diabetes that cannot be controlled by drugs, hepatorenal disease, malignant tumor, etc; - serious nervous system disease (epilepsy, convulsion or convulsion) or psychosis; - thyroid disease or history of thyroidectomy, asplenia, functional asplenia, asplenia or splenectomy resulting from any condition; - 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 non-complicated dermatitis superficial corticosteroid therapy) in the past 6 months; - long history of alcohol or drug abuse; - receipt of blood products 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; - receipt of inactivated or subunit vaccines in the past 7 days; - acute diseases or acute exacerbation of chronic diseases in the past 7 days; - axillary temperature >37.0°c; - according to the investigator's judgment, the subject has any other factors that are not suitable for the clinical trial.

- travel history / residence history of wuhan city and surrounding areas, or other communities with case reports within 14 days; - history of contact with a sars-cov-2 infection (positive in nucleic acid test) within 14 days; - have contacted patients with fever or respiratory symptoms from wuhan and surrounding areas, or from communities with case reports within 14 days; - two or more cases of fever and / or respiratory symptoms in a small contact area of volunteers, such as home, office etc. within 14 days; - history of sars-cov-2 infection; - history of asthma, history of allergy to the vaccine or vaccine components, or serious adverse reactions to the vaccine, such as urticaria, dyspnea, and angioedema; - congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.; - autoimmune disease or immunodeficiency / immunosuppression; - 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; - thyroid disease or history of thyroidectomy, spleenlessness, functional spleenlessness, spleenlessness or splenectomy resulting from any condition; - 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; - receipt of inactivated or subunit vaccines in the past 7 days; - acute diseases or acute exacerbation of chronic diseases in the past 7 days; - axillary temperature >37.0°c; - according to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial

- travel history / residence history of wuhan city and surrounding areas, or other communities with case reports within 14 days; - history of contact with a sars-cov-2 infection (positive in nucleic acid test) within 14 days; - have contacted patients with fever or respiratory symptoms from wuhan and surrounding areas, or from communities with case reports within 14 days; - two or more cases of fever and / or respiratory symptoms in a small contact area of volunteers, such as home, office etc. within 14 days; - history of sars-cov-2 infection; - history of asthma, history of allergy to the vaccine or vaccine components, or serious adverse reactions to the vaccine, such as urticaria, dyspnea, and angioedema; - congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.; - autoimmune disease or immunodeficiency / immunosuppression; - 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; - thyroid disease or history of thyroidectomy, spleenlessness, functional spleenlessness, spleenlessness or splenectomy resulting from any condition; - 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; - receipt of inactivated or subunit vaccines in the past 7 days; - acute diseases or acute exacerbation of chronic diseases in the past 7 days; - axillary temperature >37.0°c; - according to the investigator's judgment, the subject has any other factors that are not suitable for participating in the clinical trial