first-dose exclusion criteria： * confirmed cases, suspected cases, asymptomatic infections, or close contacts of the above-mentioned groups of sars-cov-2 infection (check "china disease prevention and control information system"); * axillary body temperature ≥37.3℃ before vaccination; * positive test for novel coronavirus antibody (igg+igm); * have a history of sars virus infection (self-report, on-site inquiry); * 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; * the test results of blood biochemistry, blood routine, urine routine and coagulation function-related indexes before vaccination are abnormal, which are beyond the reference value range and have clinically significant abnormalities; * severe allergic reactions (such as acute allergic reactions, urticaria, skin eczema, dyspnea, angioedema or abdominal pain) have occurred in the past; * allergy to any component of the study vaccine (such as: aluminum, histidine, etc.); * patients with convulsions, epilepsy, encephalopathy or other progressive neurological diseases (such as transverse myelitis, guillain-barre syndrome, demyelinating diseases, etc.), long-term history of alcohol and drug abuse, history of thyroidectomy, infectious diseases, mental illness medical or family history; * known or suspected diseases include: severe respiratory disease, severe liver and kidney disease, severe cardiovascular disease, uncontrolled hypertension (systolic blood pressure ≥140mmhg, diastolic blood pressure ≥90mmhg), diabetic complications, malignant tumors, various acute diseases, acute exacerbations of chronic diseases or severe chronic diseases; * have been diagnosed with congenital or acquired immunodeficiency, hiv infection, lymphoma, leukemia or other autoimmune diseases; * thrombocytopenia, history of abnormal coagulation function (such as coagulation factor deficiency, coagulation disease); * asplenia or splenectomy, functional asplenia caused by any circumstance; * are receiving anti-tb (tuberculosis) treatment; * received immune enhancement or inhibitor therapy within 3 months (continuous oral or infusion for more than 14 days); * received live attenuated vaccine within 28 days before vaccination, and received other vaccines within 14 days before vaccination; * received blood products within 3 months before vaccination; * received other study drugs within 6 months before vaccination; * planning to move before the end of the study or to be away from the local area for an extended period of time during a scheduled study visit; * the investigator judges other circumstances that are not suitable to participate in this clinical trial. exclusion criteria for second and third doses： * positive urine pregnancy test; * patients with abnormal conditions such as high fever (axillary temperature ≥39.0℃) for three days, convulsions, severe allergic reactions or any adverse reactions of the --nervous system after the previous dose of vaccination; * serious adverse reactions that are causally related to the previous dose of vaccination; * for those newly discovered or newly discovered after the previous dose of vaccine that do not meet the first-dose inclusion criteria or meet the first-dose exclusion criteria, the investigator will determine whether to continue participating in the study; * other reasons for exclusion considered by the investigator.

first-dose exclusion criteria： * confirmed cases, suspected cases, asymptomatic infections, or close contacts of the above-mentioned groups of sars-cov-2 infection (check "china disease prevention and control information system"); * axillary body temperature ≥37.3℃ before vaccination; * positive test for novel coronavirus antibody (igg+igm); * have a history of sars virus infection (self-report, on-site inquiry); * 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; * the test results of blood biochemistry, blood routine, urine routine and coagulation function-related indexes before vaccination are abnormal, which are beyond the reference value range and have clinically significant abnormalities; * severe allergic reactions (such as acute allergic reactions, urticaria, skin eczema, dyspnea, angioedema or abdominal pain) have occurred in the past; * allergy to any component of the study vaccine (such as: aluminum, histidine, etc.); * patients with convulsions, epilepsy, encephalopathy or other progressive neurological diseases (such as transverse myelitis, guillain-barre syndrome, demyelinating diseases, etc.), long-term history of alcohol and drug abuse, history of thyroidectomy, infectious diseases, mental illness medical or family history; * known or suspected diseases include: severe respiratory disease, severe liver and kidney disease, severe cardiovascular disease, uncontrolled hypertension (systolic blood pressure ≥140mmhg, diastolic blood pressure ≥90mmhg), diabetic complications, malignant tumors, various acute diseases, acute exacerbations of chronic diseases or severe chronic diseases; * have been diagnosed with congenital or acquired immunodeficiency, hiv infection, lymphoma, leukemia or other autoimmune diseases; * thrombocytopenia, history of abnormal coagulation function (such as coagulation factor deficiency, coagulation disease); * asplenia or splenectomy, functional asplenia caused by any circumstance; * are receiving anti-tb (tuberculosis) treatment; * received immune enhancement or inhibitor therapy within 3 months (continuous oral or infusion for more than 14 days); * received live attenuated vaccine within 28 days before vaccination, and received other vaccines within 14 days before vaccination; * received blood products within 3 months before vaccination; * received other study drugs within 6 months before vaccination; * planning to move before the end of the study or to be away from the local area for an extended period of time during a scheduled study visit; * the investigator judges other circumstances that are not suitable to participate in this clinical trial. exclusion criteria for second and third doses： * positive urine pregnancy test; * patients with abnormal conditions such as high fever (axillary temperature ≥39.0℃) for three days, convulsions, severe allergic reactions or any adverse reactions of the --nervous system after the previous dose of vaccination; * serious adverse reactions that are causally related to the previous dose of vaccination; * for those newly discovered or newly discovered after the previous dose of vaccine that do not meet the first-dose inclusion criteria or meet the first-dose exclusion criteria, the investigator will determine whether to continue participating in the study; * other reasons for exclusion considered by the investigator.

first-dose exclusion criteria： confirmed cases, suspected cases, asymptomatic infections, or close contacts of the above-mentioned groups of sars-cov-2 infection (check "china disease prevention and control information system"); axillary body temperature ≥37.3℃ before vaccination; positive test for novel coronavirus antibody (igg+igm); have a history of sars virus infection (self-report, on-site inquiry); 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; the test results of blood biochemistry, blood routine, urine routine and coagulation function-related indexes before vaccination are abnormal, which are beyond the reference value range and have clinically significant abnormalities; severe allergic reactions (such as acute allergic reactions, urticaria, skin eczema, dyspnea, angioedema or abdominal pain) have occurred in the past; allergy to any component of the study vaccine (such as: aluminum, histidine, etc.); patients with convulsions, epilepsy, encephalopathy or other progressive neurological diseases (such as transverse myelitis, guillain-barre syndrome, demyelinating diseases, etc.), long-term history of alcohol and drug abuse, history of thyroidectomy, infectious diseases, mental illness medical or family history; known or suspected diseases include: severe respiratory disease, severe liver and kidney disease, severe cardiovascular disease, uncontrolled hypertension (systolic blood pressure ≥140mmhg, diastolic blood pressure ≥90mmhg), diabetic complications, malignant tumors, various acute diseases, acute exacerbations of chronic diseases or severe chronic diseases; have been diagnosed with congenital or acquired immunodeficiency, hiv infection, lymphoma, leukemia or other autoimmune diseases; thrombocytopenia, history of abnormal coagulation function (such as coagulation factor deficiency, coagulation disease); asplenia or splenectomy, functional asplenia caused by any circumstance; are receiving anti-tb (tuberculosis) treatment; received immune enhancement or inhibitor therapy within 3 months (continuous oral or infusion for more than 14 days); received live attenuated vaccine within 28 days before vaccination, and received other vaccines within 14 days before vaccination; received blood products within 3 months before vaccination; received other study drugs within 6 months before vaccination; planning to move before the end of the study or to be away from the local area for an extended period of time during a scheduled study visit; the investigator judges other circumstances that are not suitable to participate in this clinical trial. exclusion criteria for second and third doses： positive urine pregnancy test; patients with abnormal conditions such as high fever (axillary temperature ≥39.0℃) for three days, convulsions, severe allergic reactions or any adverse reactions of the --nervous system after the previous dose of vaccination; serious adverse reactions that are causally related to the previous dose of vaccination; for those newly discovered or newly discovered after the previous dose of vaccine that do not meet the first-dose inclusion criteria or meet the first-dose exclusion criteria, the investigator will determine whether to continue participating in the study; other reasons for exclusion considered by the investigator.

first-dose exclusion criteria： confirmed cases, suspected cases, asymptomatic infections, or close contacts of the above-mentioned groups of sars-cov-2 infection (check "china disease prevention and control information system"); axillary body temperature ≥37.3℃ before vaccination; positive test for novel coronavirus antibody (igg+igm); have a history of sars virus infection (self-report, on-site inquiry); 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; the test results of blood biochemistry, blood routine, urine routine and coagulation function-related indexes before vaccination are abnormal, which are beyond the reference value range and have clinically significant abnormalities; severe allergic reactions (such as acute allergic reactions, urticaria, skin eczema, dyspnea, angioedema or abdominal pain) have occurred in the past; allergy to any component of the study vaccine (such as: aluminum, histidine, etc.); patients with convulsions, epilepsy, encephalopathy or other progressive neurological diseases (such as transverse myelitis, guillain-barre syndrome, demyelinating diseases, etc.), long-term history of alcohol and drug abuse, history of thyroidectomy, infectious diseases, mental illness medical or family history; known or suspected diseases include: severe respiratory disease, severe liver and kidney disease, severe cardiovascular disease, uncontrolled hypertension (systolic blood pressure ≥140mmhg, diastolic blood pressure ≥90mmhg), diabetic complications, malignant tumors, various acute diseases, acute exacerbations of chronic diseases or severe chronic diseases; have been diagnosed with congenital or acquired immunodeficiency, hiv infection, lymphoma, leukemia or other autoimmune diseases; thrombocytopenia, history of abnormal coagulation function (such as coagulation factor deficiency, coagulation disease); asplenia or splenectomy, functional asplenia caused by any circumstance; are receiving anti-tb (tuberculosis) treatment; received immune enhancement or inhibitor therapy within 3 months (continuous oral or infusion for more than 14 days); received live attenuated vaccine within 28 days before vaccination, and received other vaccines within 14 days before vaccination; received blood products within 3 months before vaccination; received other study drugs within 6 months before vaccination; planning to move before the end of the study or to be away from the local area for an extended period of time during a scheduled study visit; the investigator judges other circumstances that are not suitable to participate in this clinical trial. exclusion criteria for second and third doses： positive urine pregnancy test; patients with abnormal conditions such as high fever (axillary temperature ≥39.0℃) for three days, convulsions, severe allergic reactions or any adverse reactions of the --nervous system after the previous dose of vaccination; serious adverse reactions that are causally related to the previous dose of vaccination; for those newly discovered or newly discovered after the previous dose of vaccine that do not meet the first-dose inclusion criteria or meet the first-dose exclusion criteria, the investigator will determine whether to continue participating in the study; other reasons for exclusion considered by the investigator.