* confirmed cases or history of sars-cov-2 infection; * has a history of sars and mers virus infection; * has fever (axillary temperature ≥37.3℃), dry cough, fatigue, nasal congestion, runny nose, sore throat, myalgia, diarrhea, shortness of breath, and dyspnea within 14 days before vaccination; * positive urine pregnancy test； * axillary temperature ≥37.3℃ at the day vaccinated; * history of severe allergic reactions to vaccination (such as acute allergic reactions, urticaria, dyspnea, angioneurosis, edema, etc.) or allergies to known components of covid-19 mrna vaccine; * history or family history of convulsions, epilepsy, encephalopathy, or mental illness; * suffering from congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.; * known suffering from diseases including: acute respiratory disease (such as flu-like illness, acute cough, sore throat), severe cardiovascular disease, kidney disease, uncontrolled hypertension (systolic blood pressure \>150 mmhg, diastolic blood pressure \>90 mmhg), diabetes complications, malignant tumor, all sorts of acute illness or chronic diseases acute phase; * diagnosis with congenital or acquired immunodeficiency, hiv infection, lymphoma, leukemia, or other autoimmune disease; * abnormal coagulation function (such as lack of coagulation factor, coagulation disorders); * receiving anti-tuberculosis treatment; * long-term receipt (continuous≥7 days) of glucocorticoid (reverence value for dose: amount to≥20 mg/d prednisone equivalent), except inhaled, topical, nasal, aural and ophthalmic corticosteroids, within 6 months before screening; receipt of immunotherapy or immunosuppressant within 3 months (continuous oral or infusion for more than 14 days); * receipt of live attenuated vaccine within 28 days prior to vaccination and other vaccines within 14 days prior to vaccination; * receipt of blood products within 3 months prior to vaccination * receipt of other study drugs within 6 months prior to vaccination; * receipt of any sars-cov-2 vaccine; * other situations judged by the investigators that are not suitable for participating in this clinical trial.

* confirmed cases or history of sars-cov-2 infection; * has a history of sars and mers virus infection; * has fever (axillary temperature ≥37.3℃), dry cough, fatigue, nasal congestion, runny nose, sore throat, myalgia, diarrhea, shortness of breath, and dyspnea within 14 days before vaccination; * positive urine pregnancy test； * axillary temperature ≥37.3℃ at the day vaccinated; * history of severe allergic reactions to vaccination (such as acute allergic reactions, urticaria, dyspnea, angioneurosis, edema, etc.) or allergies to known components of covid-19 mrna vaccine; * history or family history of convulsions, epilepsy, encephalopathy, or mental illness; * suffering from congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.; * known suffering from diseases including: acute respiratory disease (such as flu-like illness, acute cough, sore throat), severe cardiovascular disease, kidney disease, uncontrolled hypertension (systolic blood pressure \>150 mmhg, diastolic blood pressure \>90 mmhg), diabetes complications, malignant tumor, all sorts of acute illness or chronic diseases acute phase; * diagnosis with congenital or acquired immunodeficiency, hiv infection, lymphoma, leukemia, or other autoimmune disease; * abnormal coagulation function (such as lack of coagulation factor, coagulation disorders); * receiving anti-tuberculosis treatment; * long-term receipt (continuous≥7 days) of glucocorticoid (reverence value for dose: amount to≥20 mg/d prednisone equivalent), except inhaled, topical, nasal, aural and ophthalmic corticosteroids, within 6 months before screening; receipt of immunotherapy or immunosuppressant within 3 months (continuous oral or infusion for more than 14 days); * receipt of live attenuated vaccine within 28 days prior to vaccination and other vaccines within 14 days prior to vaccination; * receipt of blood products within 3 months prior to vaccination * receipt of other study drugs within 6 months prior to vaccination; * receipt of any sars-cov-2 vaccine; * other situations judged by the investigators that are not suitable for participating in this clinical trial.

confirmed cases or history of sars-cov-2 infection; has a history of sars and mers virus infection; has fever (axillary temperature ≥37.3℃), dry cough, fatigue, nasal congestion, runny nose, sore throat, myalgia, diarrhea, shortness of breath, and dyspnea within 14 days before vaccination; positive urine pregnancy test； axillary temperature ≥37.3℃ at the day vaccinated; history of severe allergic reactions to vaccination (such as acute allergic reactions, urticaria, dyspnea, angioneurosis, edema, etc.) or allergies to known components of covid-19 mrna vaccine; history or family history of convulsions, epilepsy, encephalopathy, or mental illness; suffering from congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.; known suffering from diseases including: acute respiratory disease (such as flu-like illness, acute cough, sore throat), severe cardiovascular disease, kidney disease, uncontrolled hypertension (systolic blood pressure >150 mmhg, diastolic blood pressure >90 mmhg), diabetes complications, malignant tumor, all sorts of acute illness or chronic diseases acute phase; diagnosis with congenital or acquired immunodeficiency, hiv infection, lymphoma, leukemia, or other autoimmune disease; abnormal coagulation function (such as lack of coagulation factor, coagulation disorders); receiving anti-tuberculosis treatment; long-term receipt (continuous≥7 days) of glucocorticoid (reverence value for dose: amount to≥20 mg/d prednisone equivalent), except inhaled, topical, nasal, aural and ophthalmic corticosteroids, within 6 months before screening; receipt of immunotherapy or immunosuppressant within 3 months (continuous oral or infusion for more than 14 days); receipt of live attenuated vaccine within 28 days prior to vaccination and other vaccines within 14 days prior to vaccination; receipt of blood products within 3 months prior to vaccination receipt of other study drugs within 6 months prior to vaccination; receipt of any sars-cov-2 vaccine; other situations judged by the investigators that are not suitable for participating in this clinical trial.

confirmed cases or history of sars-cov-2 infection; has a history of sars and mers virus infection; has fever (axillary temperature ≥37.3℃), dry cough, fatigue, nasal congestion, runny nose, sore throat, myalgia, diarrhea, shortness of breath, and dyspnea within 14 days before vaccination; positive urine pregnancy test； axillary temperature ≥37.3℃ at the day vaccinated; history of severe allergic reactions to vaccination (such as acute allergic reactions, urticaria, dyspnea, angioneurosis, edema, etc.) or allergies to known components of covid-19 mrna vaccine; history or family history of convulsions, epilepsy, encephalopathy, or mental illness; suffering from congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.; known suffering from diseases including: acute respiratory disease (such as flu-like illness, acute cough, sore throat), severe cardiovascular disease, kidney disease, uncontrolled hypertension (systolic blood pressure >150 mmhg, diastolic blood pressure >90 mmhg), diabetes complications, malignant tumor, all sorts of acute illness or chronic diseases acute phase; diagnosis with congenital or acquired immunodeficiency, hiv infection, lymphoma, leukemia, or other autoimmune disease; abnormal coagulation function (such as lack of coagulation factor, coagulation disorders); receiving anti-tuberculosis treatment; long-term receipt (continuous≥7 days) of glucocorticoid (reverence value for dose: amount to≥20 mg/d prednisone equivalent), except inhaled, topical, nasal, aural and ophthalmic corticosteroids, within 6 months before screening; receipt of immunotherapy or immunosuppressant within 3 months (continuous oral or infusion for more than 14 days); receipt of live attenuated vaccine within 28 days prior to vaccination and other vaccines within 14 days prior to vaccination; receipt of blood products within 3 months prior to vaccination receipt of other study drugs within 6 months prior to vaccination; receipt of any sars-cov-2 vaccine; other situations judged by the investigators that are not suitable for participating in this clinical trial.