1. have received any sars-cov-2 vaccines other than 2 doses of the inactivated vaccine 2. history of severe acute respiratory syndrome (sars), coronavirus disease 2019 (covid-19), middle east respiratory syndrome (mers) and other human coronavirus infections or disease 3. positive sars-cov-2 reverse transcription-polymerase chain reaction (rt-pcr) test 4. the vital signs or physical examination are clinically significant abnormal as determined by the investigators in screening 5. fever (axillary temperature≥37.3°c) on the day of the vaccination 6. a history of severe allergy (including drugs, vaccines, and foods) or to any component of the experimental vaccine, e.g., allergic shock, laryngeal edema, anaphylactoid purpura, dyspnea, and angioedema, etc. 7. subjects have contraindications to intramuscular injection, such as having been diagnosed with thrombocytopenia, any blood clotting disorder, or receiving anticoagulant therapy 8. subjects have been diagnosed with a serious disease, congenital malformation or chronic disease (including but not limited to respiratory disease or bronchitis such as asthma, serious cardiovascular disease, serious cerebrovascular disease, kidney disease, serious or uncontrollable diabetes, autoimmune disease, thrombocytopenic purpura, thalassemia, malignant tumor, hereditary allergic constitution, etc.) that may interfere with the conduct or completion of the study 9. diagnosed with diseases may affect immune system function, including malignant tumor, congenital or acquired immune deficiency or suppression (e.g., tuberculosis, human immunodeficiency virus (hiv)), hepatitis b, hepatitis c, syphilis infection, uncontrollable autoimmune disease, no spleen or spleen dysfunction 10. history or family history of central nervous system disease, convulsions or tics, epilepsy, meningitis, neurological disorders, mental disorders, cerebritis, myelitis, guillain-barre syndrome, etc 11. long-term use of immunopotentiator or immunosuppressant therapy within 6 months prior to vaccination (continuous oral or injection for more than 14 days) 12. use of any blood or blood-related products (e.g., blood transfusion, use of human albumin, human immunoglobulin, etc.) or have received solid organ or bone marrow transplantation within 3 months prior to vaccination 13. lymph node - related diseases (such as lymphadenitis, lymph node adhesion, lymph node tuberculosis, tumor metastasis, etc.) or skin scars and fistulas at the lymph node site, or lymphadenopathy, tenderness, skin redness and swelling at the lymph node site within 7 days prior to vaccination 14. within 3 days prior to vaccination, an acute illness or attack of a chronic disease, or the use of antipyretic analgesic or anti - allergic drugs 15. other vaccines have been administered within 4 weeks prior to the trial vaccination or other vaccination schedule (except for emergency vaccinations such as rabies vaccine and tetanus vaccine) between the screening period and 28 days after the vaccination 16. participating in or planning to participate in other clinical trials (drugs or vaccines) within 3 months prior to participating in this study 17. any blood loss \>400 ml (e.g., donation of blood or blood components or injury) within 28 days prior to the screening visit, or plans to donate blood or blood components between the screening visit and 28 days post-vaccination 18. any abnormal or permanent body art (such as tattoos) at the site of the vaccination, which the researchers think to interfere with observing local reactions at the site of the vaccination 19. other circumstances considered by the investigator as inappropriate to participate in the study

1. have received any sars-cov-2 vaccines other than 2 doses of the inactivated vaccine 2. history of severe acute respiratory syndrome (sars), coronavirus disease 2019 (covid-19), middle east respiratory syndrome (mers) and other human coronavirus infections or disease 3. positive sars-cov-2 reverse transcription-polymerase chain reaction (rt-pcr) test 4. the vital signs or physical examination are clinically significant abnormal as determined by the investigators in screening 5. fever (axillary temperature≥37.3°c) on the day of the vaccination 6. a history of severe allergy (including drugs, vaccines, and foods) or to any component of the experimental vaccine, e.g., allergic shock, laryngeal edema, anaphylactoid purpura, dyspnea, and angioedema, etc. 7. subjects have contraindications to intramuscular injection, such as having been diagnosed with thrombocytopenia, any blood clotting disorder, or receiving anticoagulant therapy 8. subjects have been diagnosed with a serious disease, congenital malformation or chronic disease (including but not limited to respiratory disease or bronchitis such as asthma, serious cardiovascular disease, serious cerebrovascular disease, kidney disease, serious or uncontrollable diabetes, autoimmune disease, thrombocytopenic purpura, thalassemia, malignant tumor, hereditary allergic constitution, etc.) that may interfere with the conduct or completion of the study 9. diagnosed with diseases may affect immune system function, including malignant tumor, congenital or acquired immune deficiency or suppression (e.g., tuberculosis, human immunodeficiency virus (hiv)), hepatitis b, hepatitis c, syphilis infection, uncontrollable autoimmune disease, no spleen or spleen dysfunction 10. history or family history of central nervous system disease, convulsions or tics, epilepsy, meningitis, neurological disorders, mental disorders, cerebritis, myelitis, guillain-barre syndrome, etc 11. long-term use of immunopotentiator or immunosuppressant therapy within 6 months prior to vaccination (continuous oral or injection for more than 14 days) 12. use of any blood or blood-related products (e.g., blood transfusion, use of human albumin, human immunoglobulin, etc.) or have received solid organ or bone marrow transplantation within 3 months prior to vaccination 13. lymph node - related diseases (such as lymphadenitis, lymph node adhesion, lymph node tuberculosis, tumor metastasis, etc.) or skin scars and fistulas at the lymph node site, or lymphadenopathy, tenderness, skin redness and swelling at the lymph node site within 7 days prior to vaccination 14. within 3 days prior to vaccination, an acute illness or attack of a chronic disease, or the use of antipyretic analgesic or anti - allergic drugs 15. other vaccines have been administered within 4 weeks prior to the trial vaccination or other vaccination schedule (except for emergency vaccinations such as rabies vaccine and tetanus vaccine) between the screening period and 28 days after the vaccination 16. participating in or planning to participate in other clinical trials (drugs or vaccines) within 3 months prior to participating in this study 17. any blood loss \>400 ml (e.g., donation of blood or blood components or injury) within 28 days prior to the screening visit, or plans to donate blood or blood components between the screening visit and 28 days post-vaccination 18. any abnormal or permanent body art (such as tattoos) at the site of the vaccination, which the researchers think to interfere with observing local reactions at the site of the vaccination 19. other circumstances considered by the investigator as inappropriate to participate in the study

have received any sars-cov-2 vaccines other than 2 doses of the inactivated vaccine history of severe acute respiratory syndrome (sars), coronavirus disease 2019 (covid-19), middle east respiratory syndrome (mers) and other human coronavirus infections or disease positive sars-cov-2 reverse transcription-polymerase chain reaction (rt-pcr) test the vital signs or physical examination are clinically significant abnormal as determined by the investigators in screening fever (axillary temperature≥37.3°c) on the day of the vaccination a history of severe allergy (including drugs, vaccines, and foods) or to any component of the experimental vaccine, e.g., allergic shock, laryngeal edema, anaphylactoid purpura, dyspnea, and angioedema, etc. subjects have contraindications to intramuscular injection, such as having been diagnosed with thrombocytopenia, any blood clotting disorder, or receiving anticoagulant therapy subjects have been diagnosed with a serious disease, congenital malformation or chronic disease (including but not limited to respiratory disease or bronchitis such as asthma, serious cardiovascular disease, serious cerebrovascular disease, kidney disease, serious or uncontrollable diabetes, autoimmune disease, thrombocytopenic purpura, thalassemia, malignant tumor, hereditary allergic constitution, etc.) that may interfere with the conduct or completion of the study diagnosed with diseases may affect immune system function, including malignant tumor, congenital or acquired immune deficiency or suppression (e.g., tuberculosis, human immunodeficiency virus (hiv)), hepatitis b, hepatitis c, syphilis infection, uncontrollable autoimmune disease, no spleen or spleen dysfunction history or family history of central nervous system disease, convulsions or tics, epilepsy, meningitis, neurological disorders, mental disorders, cerebritis, myelitis, guillain-barre syndrome, etc long-term use of immunopotentiator or immunosuppressant therapy within 6 months prior to vaccination (continuous oral or injection for more than 14 days) use of any blood or blood-related products (e.g., blood transfusion, use of human albumin, human immunoglobulin, etc.) or have received solid organ or bone marrow transplantation within 3 months prior to vaccination lymph node - related diseases (such as lymphadenitis, lymph node adhesion, lymph node tuberculosis, tumor metastasis, etc.) or skin scars and fistulas at the lymph node site, or lymphadenopathy, tenderness, skin redness and swelling at the lymph node site within 7 days prior to vaccination within 3 days prior to vaccination, an acute illness or attack of a chronic disease, or the use of antipyretic analgesic or anti - allergic drugs other vaccines have been administered within 4 weeks prior to the trial vaccination or other vaccination schedule (except for emergency vaccinations such as rabies vaccine and tetanus vaccine) between the screening period and 28 days after the vaccination participating in or planning to participate in other clinical trials (drugs or vaccines) within 3 months prior to participating in this study any blood loss >400 ml (e.g., donation of blood or blood components or injury) within 28 days prior to the screening visit, or plans to donate blood or blood components between the screening visit and 28 days post-vaccination any abnormal or permanent body art (such as tattoos) at the site of the vaccination, which the researchers think to interfere with observing local reactions at the site of the vaccination other circumstances considered by the investigator as inappropriate to participate in the study

have received any sars-cov-2 vaccines other than 2 doses of the inactivated vaccine history of severe acute respiratory syndrome (sars), coronavirus disease 2019 (covid-19), middle east respiratory syndrome (mers) and other human coronavirus infections or disease positive sars-cov-2 reverse transcription-polymerase chain reaction (rt-pcr) test the vital signs or physical examination are clinically significant abnormal as determined by the investigators in screening fever (axillary temperature≥37.3°c) on the day of the vaccination a history of severe allergy (including drugs, vaccines, and foods) or to any component of the experimental vaccine, e.g., allergic shock, laryngeal edema, anaphylactoid purpura, dyspnea, and angioedema, etc. subjects have contraindications to intramuscular injection, such as having been diagnosed with thrombocytopenia, any blood clotting disorder, or receiving anticoagulant therapy subjects have been diagnosed with a serious disease, congenital malformation or chronic disease (including but not limited to respiratory disease or bronchitis such as asthma, serious cardiovascular disease, serious cerebrovascular disease, kidney disease, serious or uncontrollable diabetes, autoimmune disease, thrombocytopenic purpura, thalassemia, malignant tumor, hereditary allergic constitution, etc.) that may interfere with the conduct or completion of the study diagnosed with diseases may affect immune system function, including malignant tumor, congenital or acquired immune deficiency or suppression (e.g., tuberculosis, human immunodeficiency virus (hiv)), hepatitis b, hepatitis c, syphilis infection, uncontrollable autoimmune disease, no spleen or spleen dysfunction history or family history of central nervous system disease, convulsions or tics, epilepsy, meningitis, neurological disorders, mental disorders, cerebritis, myelitis, guillain-barre syndrome, etc long-term use of immunopotentiator or immunosuppressant therapy within 6 months prior to vaccination (continuous oral or injection for more than 14 days) use of any blood or blood-related products (e.g., blood transfusion, use of human albumin, human immunoglobulin, etc.) or have received solid organ or bone marrow transplantation within 3 months prior to vaccination lymph node - related diseases (such as lymphadenitis, lymph node adhesion, lymph node tuberculosis, tumor metastasis, etc.) or skin scars and fistulas at the lymph node site, or lymphadenopathy, tenderness, skin redness and swelling at the lymph node site within 7 days prior to vaccination within 3 days prior to vaccination, an acute illness or attack of a chronic disease, or the use of antipyretic analgesic or anti - allergic drugs other vaccines have been administered within 4 weeks prior to the trial vaccination or other vaccination schedule (except for emergency vaccinations such as rabies vaccine and tetanus vaccine) between the screening period and 28 days after the vaccination participating in or planning to participate in other clinical trials (drugs or vaccines) within 3 months prior to participating in this study any blood loss >400 ml (e.g., donation of blood or blood components or injury) within 28 days prior to the screening visit, or plans to donate blood or blood components between the screening visit and 28 days post-vaccination any abnormal or permanent body art (such as tattoos) at the site of the vaccination, which the researchers think to interfere with observing local reactions at the site of the vaccination other circumstances considered by the investigator as inappropriate to participate in the study

have received any sars-cov-2 vaccines other than 2 doses of the inactivated vaccine history of severe acute respiratory syndrome (sars), coronavirus disease 2019 (covid-19), middle east respiratory syndrome (mers) and other human coronavirus infections or disease negative sars-cov-2 reverse transcription-polymerase chain reaction (rt-pcr) test the vital signs or physical examination are clinically significant abnormal as determined by the investigators in screening fever (axillary temperature≥37.3°c) on the day of the vaccination a history of severe allergy (including drugs, vaccines, and foods) or to any component of the experimental vaccine, e.g., allergic shock, laryngeal edema, anaphylactoid purpura, dyspnea, and angioedema, etc. subjects have contraindications to intramuscular injection, such as having been diagnosed with thrombocytopenia, any blood clotting disorder, or receiving anticoagulant therapy subjects have been diagnosed with a serious disease, congenital malformation or chronic disease (including but not limited to respiratory disease or bronchitis such as asthma, serious cardiovascular disease, serious cerebrovascular disease, kidney disease, serious or uncontrollable diabetes, autoimmune disease, thrombocytopenic purpura, thalassemia, malignant tumor, hereditary allergic constitution, etc.) that may interfere with the conduct or completion of the study diagnosed with diseases may affect immune system function, including malignant tumor, congenital or acquired immune deficiency or suppression (e.g., tuberculosis, human immunodeficiency virus (hiv)), hepatitis b, hepatitis c, syphilis infection, uncontrollable autoimmune disease, no spleen or spleen dysfunction history or family history of central nervous system disease, convulsions or tics, epilepsy, meningitis, neurological disorders, mental disorders, cerebritis, myelitis, guillain-barre syndrome, etc long-term use of immunopotentiator or immunosuppressant therapy within 6 months prior to vaccination (continuous oral or injection for more than 14 days) use of any blood or blood-related products (e.g., blood transfusion, use of human albumin, human immunoglobulin, etc.) or have received solid organ or bone marrow transplantation within 3 months prior to vaccination lymph node - related diseases (such as lymphadenitis, lymph node adhesion, lymph node tuberculosis, tumor metastasis, etc.) or skin scars and fistulas at the lymph node site, or lymphadenopathy, tenderness, skin redness and swelling at the lymph node site within 7 days prior to vaccination within 3 days prior to vaccination, an acute illness or attack of a chronic disease, or the use of antipyretic analgesic or anti - allergic drugs other vaccines have been administered within 4 weeks prior to the trial vaccination or other vaccination schedule (except for emergency vaccinations such as rabies vaccine and tetanus vaccine) between the screening period and 28 days after the vaccination participating in or planning to participate in other clinical trials (drugs or vaccines) within 3 months prior to participating in this study any blood loss >400 ml (e.g., donation of blood or blood components or injury) within 28 days prior to the screening visit, or plans to donate blood or blood components between the screening visit and 28 days post-vaccination any abnormal or permanent body art (such as tattoos) at the site of the vaccination, which the researchers think to interfere with observing local reactions at the site of the vaccination other circumstances considered by the investigator as inappropriate to participate in the study

have received any sars-cov-2 vaccines other than 2 doses of the inactivated vaccine history of severe acute respiratory syndrome (sars), coronavirus disease 2019 (covid-19), middle east respiratory syndrome (mers) and other human coronavirus infections or disease negative sars-cov-2 reverse transcription-polymerase chain reaction (rt-pcr) test the vital signs or physical examination are clinically significant abnormal as determined by the investigators in screening fever (axillary temperature≥37.3°c) on the day of the vaccination a history of severe allergy (including drugs, vaccines, and foods) or to any component of the experimental vaccine, e.g., allergic shock, laryngeal edema, anaphylactoid purpura, dyspnea, and angioedema, etc. subjects have contraindications to intramuscular injection, such as having been diagnosed with thrombocytopenia, any blood clotting disorder, or receiving anticoagulant therapy subjects have been diagnosed with a serious disease, congenital malformation or chronic disease (including but not limited to respiratory disease or bronchitis such as asthma, serious cardiovascular disease, serious cerebrovascular disease, kidney disease, serious or uncontrollable diabetes, autoimmune disease, thrombocytopenic purpura, thalassemia, malignant tumor, hereditary allergic constitution, etc.) that may interfere with the conduct or completion of the study diagnosed with diseases may affect immune system function, including malignant tumor, congenital or acquired immune deficiency or suppression (e.g., tuberculosis, human immunodeficiency virus (hiv)), hepatitis b, hepatitis c, syphilis infection, uncontrollable autoimmune disease, no spleen or spleen dysfunction history or family history of central nervous system disease, convulsions or tics, epilepsy, meningitis, neurological disorders, mental disorders, cerebritis, myelitis, guillain-barre syndrome, etc long-term use of immunopotentiator or immunosuppressant therapy within 6 months prior to vaccination (continuous oral or injection for more than 14 days) use of any blood or blood-related products (e.g., blood transfusion, use of human albumin, human immunoglobulin, etc.) or have received solid organ or bone marrow transplantation within 3 months prior to vaccination lymph node - related diseases (such as lymphadenitis, lymph node adhesion, lymph node tuberculosis, tumor metastasis, etc.) or skin scars and fistulas at the lymph node site, or lymphadenopathy, tenderness, skin redness and swelling at the lymph node site within 7 days prior to vaccination within 3 days prior to vaccination, an acute illness or attack of a chronic disease, or the use of antipyretic analgesic or anti - allergic drugs other vaccines have been administered within 4 weeks prior to the trial vaccination or other vaccination schedule (except for emergency vaccinations such as rabies vaccine and tetanus vaccine) between the screening period and 28 days after the vaccination participating in or planning to participate in other clinical trials (drugs or vaccines) within 3 months prior to participating in this study any blood loss >400 ml (e.g., donation of blood or blood components or injury) within 28 days prior to the screening visit, or plans to donate blood or blood components between the screening visit and 28 days post-vaccination any abnormal or permanent body art (such as tattoos) at the site of the vaccination, which the researchers think to interfere with observing local reactions at the site of the vaccination other circumstances considered by the investigator as inappropriate to participate in the study