1. laboratory confirmed sars-cov-2 infection, defined by the result of sars-cov-2 rt-pcr assay is positive. 2. medical history of covid-19 disease with confirmed clinical diagnosis. 3. fever (oral temperature ≥ 37.5°c / axillary temperature ≥ 37.3°c) on the day of vaccination. or having fever within recent 72 hours before the vaccination. 4. having abnormal results of clinical laboratory testing during screening, which is judged by the investigator with clinical significance, including the hematology, liver function, renal function, other blood chemistry, and coagulation function. 5. history of severe allergic disease or reactions likely to be exacerbated by any component of recov or covid-19 vaccine (vero cell), inactivated, such as allergic shock, allergic laryngeal edema, allergic purpura, thrombocytopaenic purpura, local hypersensitive necrosis reaction (arthus reaction), prior history of serious adverse reaction to any vaccine or drug, such as allergy, urticaria eczema, dyspnea, and angioneurotic edema. 6. having malignant tumor (except for skin basal cell carcinoma or carcinoma uterine cervix in situ), immune disease (e.g., human immunodeficiency virus \[hiv\] infection, systemic lupus erythematosus, rheumatoid arthritis, alienia or splenectomy, and other immune disease that may influence immune response at the investigator's discretion). 7. having severe and/or uncontrolled conditions, including but not limited to, acute infectious disease, cardiovascular disease, respiratory disease (including tuberculosis under anti-tuberculosis therapy), gastrointestinal disease, liver disease, renal disease, hematology disease, endocrine disorder, psychiatric condition and neurological illness (e.g., medical or family history of seizure, epilepsy, encephalopathy). mild/moderate well-controlled comorbidities are allowed to participate. 8. having bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following intramuscular injections or venipuncture. 9. received immunosuppressant or other immunomodulators, antiallergic therapy, or cytotoxicity therapy for 14 or more consecutive days within 6 months before the study vaccination. local administration of immunosuppressant or immunomodulator is allowed (e.g., ointment, eye drops, inhalation, or nasal spray). drugs for local administration should not be given at a dose over the recommended level in package insert or participants should have no signs of systemic exposure. 10. administration of immunoglobulin and/or blood product within 3 months before the study vaccination or plan to use that during the study. 11. continuous use of anticoagulants, such as coumarins and related anticoagulants (e.g., warfarin) or novel oral anticoagulants (e.g., apixaban, rivaroxaban, dabigatran and edoxaban). 12. used other investigational drug or interventional device within 1 month before the study vaccination or plan to use that during the study, or are using other investigational drug or are within 5 half-lives after the last dose of the investigational drug. 13. used a subunit or inactivated vaccine within 14 days or an attenuated live vaccine within 1 month (30 days) before the study vaccination, or plan to receive any other vaccines except for the seasonal influenza vaccine, or other vaccines for emergency use (e.g., to prevent tetanus and rabies) during the study. 14. prior receipt of any investigational or licensed covid-19 vaccine except for the primary vaccination with inactivated vaccines according to the protocol, or plan to receive any covid-19 vaccine except for the investigational products during the study stage. 15. suspected or known current alcohol or drug dependency. 16. having contraindications for intramuscular injection or intravenous blood sampling. 17. pregnancy, lactation or plan to become pregnant within 90 days after receiving study vaccine. 18. staff of study site, sponsor, and contract research organization (cro) taking part in study conduct. 19. at investigator's discretion, any other significant disease, disorder or finding that may increase the risk because of participation in the study, or prevent from participation in the study, or impair interpretation of the study data.

1. laboratory confirmed sars-cov-2 infection, defined by the result of sars-cov-2 rt-pcr assay is positive. 2. medical history of covid-19 disease with confirmed clinical diagnosis. 3. fever (oral temperature ≥ 37.5°c / axillary temperature ≥ 37.3°c) on the day of vaccination. or having fever within recent 72 hours before the vaccination. 4. having abnormal results of clinical laboratory testing during screening, which is judged by the investigator with clinical significance, including the hematology, liver function, renal function, other blood chemistry, and coagulation function. 5. history of severe allergic disease or reactions likely to be exacerbated by any component of recov or covid-19 vaccine (vero cell), inactivated, such as allergic shock, allergic laryngeal edema, allergic purpura, thrombocytopaenic purpura, local hypersensitive necrosis reaction (arthus reaction), prior history of serious adverse reaction to any vaccine or drug, such as allergy, urticaria eczema, dyspnea, and angioneurotic edema. 6. having malignant tumor (except for skin basal cell carcinoma or carcinoma uterine cervix in situ), immune disease (e.g., human immunodeficiency virus \[hiv\] infection, systemic lupus erythematosus, rheumatoid arthritis, alienia or splenectomy, and other immune disease that may influence immune response at the investigator's discretion). 7. having severe and/or uncontrolled conditions, including but not limited to, acute infectious disease, cardiovascular disease, respiratory disease (including tuberculosis under anti-tuberculosis therapy), gastrointestinal disease, liver disease, renal disease, hematology disease, endocrine disorder, psychiatric condition and neurological illness (e.g., medical or family history of seizure, epilepsy, encephalopathy). mild/moderate well-controlled comorbidities are allowed to participate. 8. having bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following intramuscular injections or venipuncture. 9. received immunosuppressant or other immunomodulators, antiallergic therapy, or cytotoxicity therapy for 14 or more consecutive days within 6 months before the study vaccination. local administration of immunosuppressant or immunomodulator is allowed (e.g., ointment, eye drops, inhalation, or nasal spray). drugs for local administration should not be given at a dose over the recommended level in package insert or participants should have no signs of systemic exposure. 10. administration of immunoglobulin and/or blood product within 3 months before the study vaccination or plan to use that during the study. 11. continuous use of anticoagulants, such as coumarins and related anticoagulants (e.g., warfarin) or novel oral anticoagulants (e.g., apixaban, rivaroxaban, dabigatran and edoxaban). 12. used other investigational drug or interventional device within 1 month before the study vaccination or plan to use that during the study, or are using other investigational drug or are within 5 half-lives after the last dose of the investigational drug. 13. used a subunit or inactivated vaccine within 14 days or an attenuated live vaccine within 1 month (30 days) before the study vaccination, or plan to receive any other vaccines except for the seasonal influenza vaccine, or other vaccines for emergency use (e.g., to prevent tetanus and rabies) during the study. 14. prior receipt of any investigational or licensed covid-19 vaccine except for the primary vaccination with inactivated vaccines according to the protocol, or plan to receive any covid-19 vaccine except for the investigational products during the study stage. 15. suspected or known current alcohol or drug dependency. 16. having contraindications for intramuscular injection or intravenous blood sampling. 17. pregnancy, lactation or plan to become pregnant within 90 days after receiving study vaccine. 18. staff of study site, sponsor, and contract research organization (cro) taking part in study conduct. 19. at investigator's discretion, any other significant disease, disorder or finding that may increase the risk because of participation in the study, or prevent from participation in the study, or impair interpretation of the study data.

laboratory confirmed sars-cov-2 infection, defined by the result of sars-cov-2 rt-pcr assay is positive. medical history of covid-19 disease with confirmed clinical diagnosis. fever (oral temperature ≥ 37.5°c / axillary temperature ≥ 37.3°c) on the day of vaccination. or having fever within recent 72 hours before the vaccination. having abnormal results of clinical laboratory testing during screening, which is judged by the investigator with clinical significance, including the hematology, liver function, renal function, other blood chemistry, and coagulation function. history of severe allergic disease or reactions likely to be exacerbated by any component of recov or covid-19 vaccine (vero cell), inactivated, such as allergic shock, allergic laryngeal edema, allergic purpura, thrombocytopaenic purpura, local hypersensitive necrosis reaction (arthus reaction), prior history of serious adverse reaction to any vaccine or drug, such as allergy, urticaria eczema, dyspnea, and angioneurotic edema. having malignant tumor (except for skin basal cell carcinoma or carcinoma uterine cervix in situ), immune disease (e.g., human immunodeficiency virus [hiv] infection, systemic lupus erythematosus, rheumatoid arthritis, alienia or splenectomy, and other immune disease that may influence immune response at the investigator's discretion). having severe and/or uncontrolled conditions, including but not limited to, acute infectious disease, cardiovascular disease, respiratory disease (including tuberculosis under anti-tuberculosis therapy), gastrointestinal disease, liver disease, renal disease, hematology disease, endocrine disorder, psychiatric condition and neurological illness (e.g., medical or family history of seizure, epilepsy, encephalopathy). mild/moderate well-controlled comorbidities are allowed to participate. having bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following intramuscular injections or venipuncture. received immunosuppressant or other immunomodulators, antiallergic therapy, or cytotoxicity therapy for 14 or more consecutive days within 6 months before the study vaccination. local administration of immunosuppressant or immunomodulator is allowed (e.g., ointment, eye drops, inhalation, or nasal spray). drugs for local administration should not be given at a dose over the recommended level in package insert or participants should have no signs of systemic exposure. administration of immunoglobulin and/or blood product within 3 months before the study vaccination or plan to use that during the study. continuous use of anticoagulants, such as coumarins and related anticoagulants (e.g., warfarin) or novel oral anticoagulants (e.g., apixaban, rivaroxaban, dabigatran and edoxaban). used other investigational drug or interventional device within 1 month before the study vaccination or plan to use that during the study, or are using other investigational drug or are within 5 half-lives after the last dose of the investigational drug. used a subunit or inactivated vaccine within 14 days or an attenuated live vaccine within 1 month (30 days) before the study vaccination, or plan to receive any other vaccines except for the seasonal influenza vaccine, or other vaccines for emergency use (e.g., to prevent tetanus and rabies) during the study. prior receipt of any investigational or licensed covid-19 vaccine except for the primary vaccination with inactivated vaccines according to the protocol, or plan to receive any covid-19 vaccine except for the investigational products during the study stage. suspected or known current alcohol or drug dependency. having contraindications for intramuscular injection or intravenous blood sampling. pregnancy, lactation or plan to become pregnant within 90 days after receiving study vaccine. staff of study site, sponsor, and contract research organization (cro) taking part in study conduct. at investigator's discretion, any other significant disease, disorder or finding that may increase the risk because of participation in the study, or prevent from participation in the study, or impair interpretation of the study data.

laboratory confirmed sars-cov-2 infection, defined by the result of sars-cov-2 rt-pcr assay is positive. medical history of covid-19 disease with confirmed clinical diagnosis. fever (oral temperature ≥ 37.5°c / axillary temperature ≥ 37.3°c) on the day of vaccination. or having fever within recent 72 hours before the vaccination. having abnormal results of clinical laboratory testing during screening, which is judged by the investigator with clinical significance, including the hematology, liver function, renal function, other blood chemistry, and coagulation function. history of severe allergic disease or reactions likely to be exacerbated by any component of recov or covid-19 vaccine (vero cell), inactivated, such as allergic shock, allergic laryngeal edema, allergic purpura, thrombocytopaenic purpura, local hypersensitive necrosis reaction (arthus reaction), prior history of serious adverse reaction to any vaccine or drug, such as allergy, urticaria eczema, dyspnea, and angioneurotic edema. having malignant tumor (except for skin basal cell carcinoma or carcinoma uterine cervix in situ), immune disease (e.g., human immunodeficiency virus [hiv] infection, systemic lupus erythematosus, rheumatoid arthritis, alienia or splenectomy, and other immune disease that may influence immune response at the investigator's discretion). having severe and/or uncontrolled conditions, including but not limited to, acute infectious disease, cardiovascular disease, respiratory disease (including tuberculosis under anti-tuberculosis therapy), gastrointestinal disease, liver disease, renal disease, hematology disease, endocrine disorder, psychiatric condition and neurological illness (e.g., medical or family history of seizure, epilepsy, encephalopathy). mild/moderate well-controlled comorbidities are allowed to participate. having bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following intramuscular injections or venipuncture. received immunosuppressant or other immunomodulators, antiallergic therapy, or cytotoxicity therapy for 14 or more consecutive days within 6 months before the study vaccination. local administration of immunosuppressant or immunomodulator is allowed (e.g., ointment, eye drops, inhalation, or nasal spray). drugs for local administration should not be given at a dose over the recommended level in package insert or participants should have no signs of systemic exposure. administration of immunoglobulin and/or blood product within 3 months before the study vaccination or plan to use that during the study. continuous use of anticoagulants, such as coumarins and related anticoagulants (e.g., warfarin) or novel oral anticoagulants (e.g., apixaban, rivaroxaban, dabigatran and edoxaban). used other investigational drug or interventional device within 1 month before the study vaccination or plan to use that during the study, or are using other investigational drug or are within 5 half-lives after the last dose of the investigational drug. used a subunit or inactivated vaccine within 14 days or an attenuated live vaccine within 1 month (30 days) before the study vaccination, or plan to receive any other vaccines except for the seasonal influenza vaccine, or other vaccines for emergency use (e.g., to prevent tetanus and rabies) during the study. prior receipt of any investigational or licensed covid-19 vaccine except for the primary vaccination with inactivated vaccines according to the protocol, or plan to receive any covid-19 vaccine except for the investigational products during the study stage. suspected or known current alcohol or drug dependency. having contraindications for intramuscular injection or intravenous blood sampling. pregnancy, lactation or plan to become pregnant within 90 days after receiving study vaccine. staff of study site, sponsor, and contract research organization (cro) taking part in study conduct. at investigator's discretion, any other significant disease, disorder or finding that may increase the risk because of participation in the study, or prevent from participation in the study, or impair interpretation of the study data.