medical conditions 1. any clinically significant respiratory symptoms (e.g. cough, sore throat), febrile illness (tympanic temperature \>38°c), or acute illness within 72 hours prior to the 1st study vaccination. a prospective participant should not be included until 72 hours after the condition has resolved. 2. history of virologically-confirmed covid-19 disease, or definite or suspected exposure to anyone known to have sars-cov-2 infection 3. history of virologically-confirmed sars or mers disease 4. history of congenital, hereditary, acquired immunodeficiency, or autoimmune disease 5. any positive test results for hepatitis b, c, or hiv at screening 6. history of bleeding disorder or thrombocytopenia which is contraindicating intramuscular vaccination in the investigator's opinion 7. history of hypersensitivity and severe allergic reaction (e.g. anaphylaxis, guillain-barre syndrome) to any vaccines or components of the study intervention 8. history of malignancy within 5 years prior to the 1st study vaccination 9. significant chronic illness that, in the opinion of the investigator, might increase risk of severe covid-19, or interfere with the evaluation of the study objectives (e.g. asthma, chronic pulmonary disease, cardiovascular disease, chronic liver disease, diabetes mellitus, uncontrolled hypertension, renal disorders) 10. history of, or planned surgery under general anesthesia from 1 year prior to the 1st study vaccination through the study period 11. any other conditions which, in the opinion of the investigator, might interfere with the evaluation of the study objectives (e.g. neurologic or psychiatric conditions) 12. female participants who are pregnant or breastfeeding 13. current smokers or a recent smoking history within 12 weeks prior to the 1st study vaccination. occasional smokers who smoke up to 10 cigarettes per month may be allowed to participate at the investigator's discretion prior/concomitant therapy 14. receipt of any medications or vaccinations intended to prevent covid-19. 15. receipt of any vaccine within 4 weeks prior to the 1st study vaccination or planned receipt of any vaccine from enrollment through 28 days after the last study vaccination (visit 7), except for influenza vaccination, which may be received at least 2 weeks prior to the 1st study vaccination. this exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines 16. receipt of immunoglobulins and/or any blood or blood products within 12 weeks prior to the 1st study vaccination 17. chronic use (more than 2 consecutive weeks) of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy (≥10mg prednisone/day or equivalent for more than 2 consecutive weeks) within 12 weeks prior to the 1st vaccination. the use of topical and nasal glucocorticoids will be permitted. prior/concurrent clinical study experience 18. participation in another clinical study involving study intervention within 6 months prior to the 1st study vaccination, or concurrent, planned participation in another clinical study with study intervention during this study period. other exclusions 19. investigators, or study staff who are directly involved in the conduct of this study or supervised by the investigator, and their respective family members. 20. healthcare worker or emergency response personnel in an occupation with a high risk of exposure to sars-cov-2

medical conditions 1. any clinically significant respiratory symptoms (e.g. cough, sore throat), febrile illness (tympanic temperature \>38°c), or acute illness within 72 hours prior to the 1st study vaccination. a prospective participant should not be included until 72 hours after the condition has resolved. 2. history of virologically-confirmed covid-19 disease, or definite or suspected exposure to anyone known to have sars-cov-2 infection 3. history of virologically-confirmed sars or mers disease 4. history of congenital, hereditary, acquired immunodeficiency, or autoimmune disease 5. any positive test results for hepatitis b, c, or hiv at screening 6. history of bleeding disorder or thrombocytopenia which is contraindicating intramuscular vaccination in the investigator's opinion 7. history of hypersensitivity and severe allergic reaction (e.g. anaphylaxis, guillain-barre syndrome) to any vaccines or components of the study intervention 8. history of malignancy within 5 years prior to the 1st study vaccination 9. significant chronic illness that, in the opinion of the investigator, might increase risk of severe covid-19, or interfere with the evaluation of the study objectives (e.g. asthma, chronic pulmonary disease, cardiovascular disease, chronic liver disease, diabetes mellitus, uncontrolled hypertension, renal disorders) 10. history of, or planned surgery under general anesthesia from 1 year prior to the 1st study vaccination through the study period 11. any other conditions which, in the opinion of the investigator, might interfere with the evaluation of the study objectives (e.g. neurologic or psychiatric conditions) 12. female participants who are pregnant or breastfeeding 13. current smokers or a recent smoking history within 12 weeks prior to the 1st study vaccination. occasional smokers who smoke up to 10 cigarettes per month may be allowed to participate at the investigator's discretion prior/concomitant therapy 14. receipt of any medications or vaccinations intended to prevent covid-19. 15. receipt of any vaccine within 4 weeks prior to the 1st study vaccination or planned receipt of any vaccine from enrollment through 28 days after the last study vaccination (visit 7), except for influenza vaccination, which may be received at least 2 weeks prior to the 1st study vaccination. this exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines 16. receipt of immunoglobulins and/or any blood or blood products within 12 weeks prior to the 1st study vaccination 17. chronic use (more than 2 consecutive weeks) of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy (≥10mg prednisone/day or equivalent for more than 2 consecutive weeks) within 12 weeks prior to the 1st vaccination. the use of topical and nasal glucocorticoids will be permitted. prior/concurrent clinical study experience 18. participation in another clinical study involving study intervention within 6 months prior to the 1st study vaccination, or concurrent, planned participation in another clinical study with study intervention during this study period. other exclusions 19. investigators, or study staff who are directly involved in the conduct of this study or supervised by the investigator, and their respective family members. 20. healthcare worker or emergency response personnel in an occupation with a high risk of exposure to sars-cov-2

medical conditions any clinically significant respiratory symptoms (e.g. cough, sore throat), febrile illness (tympanic temperature >38°c), or acute illness within 72 hours prior to the 1st study vaccination. a prospective participant should not be included until 72 hours after the condition has resolved. history of virologically-confirmed covid-19 disease, or definite or suspected exposure to anyone known to have sars-cov-2 infection history of virologically-confirmed sars or mers disease history of congenital, hereditary, acquired immunodeficiency, or autoimmune disease any positive test results for hepatitis b, c, or hiv at screening history of bleeding disorder or thrombocytopenia which is contraindicating intramuscular vaccination in the investigator's opinion history of hypersensitivity and severe allergic reaction (e.g. anaphylaxis, guillain-barre syndrome) to any vaccines or components of the study intervention history of malignancy within 5 years prior to the 1st study vaccination significant chronic illness that, in the opinion of the investigator, might increase risk of severe covid-19, or interfere with the evaluation of the study objectives (e.g. asthma, chronic pulmonary disease, cardiovascular disease, chronic liver disease, diabetes mellitus, uncontrolled hypertension, renal disorders) history of, or planned surgery under general anesthesia from 1 year prior to the 1st study vaccination through the study period any other conditions which, in the opinion of the investigator, might interfere with the evaluation of the study objectives (e.g. neurologic or psychiatric conditions) female participants who are pregnant or breastfeeding current smokers or a recent smoking history within 12 weeks prior to the 1st study vaccination. occasional smokers who smoke up to 10 cigarettes per month may be allowed to participate at the investigator's discretion prior/concomitant therapy receipt of any medications or vaccinations intended to prevent covid-19. receipt of any vaccine within 4 weeks prior to the 1st study vaccination or planned receipt of any vaccine from enrollment through 28 days after the last study vaccination (visit 7), except for influenza vaccination, which may be received at least 2 weeks prior to the 1st study vaccination. this exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines receipt of immunoglobulins and/or any blood or blood products within 12 weeks prior to the 1st study vaccination chronic use (more than 2 consecutive weeks) of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy (≥10mg prednisone/day or equivalent for more than 2 consecutive weeks) within 12 weeks prior to the 1st vaccination. the use of topical and nasal glucocorticoids will be permitted. prior/concurrent clinical study experience participation in another clinical study involving study intervention within 6 months prior to the 1st study vaccination, or concurrent, planned participation in another clinical study with study intervention during this study period. other exclusions investigators, or study staff who are directly involved in the conduct of this study or supervised by the investigator, and their respective family members. healthcare worker or emergency response personnel in an occupation with a high risk of exposure to sars-cov-2

medical conditions any clinically significant respiratory symptoms (e.g. cough, sore throat), febrile illness (tympanic temperature >38°c), or acute illness within 72 hours prior to the 1st study vaccination. a prospective participant should not be included until 72 hours after the condition has resolved. history of virologically-confirmed covid-19 disease, or definite or suspected exposure to anyone known to have sars-cov-2 infection history of virologically-confirmed sars or mers disease history of congenital, hereditary, acquired immunodeficiency, or autoimmune disease any positive test results for hepatitis b, c, or hiv at screening history of bleeding disorder or thrombocytopenia which is contraindicating intramuscular vaccination in the investigator's opinion history of hypersensitivity and severe allergic reaction (e.g. anaphylaxis, guillain-barre syndrome) to any vaccines or components of the study intervention history of malignancy within 5 years prior to the 1st study vaccination significant chronic illness that, in the opinion of the investigator, might increase risk of severe covid-19, or interfere with the evaluation of the study objectives (e.g. asthma, chronic pulmonary disease, cardiovascular disease, chronic liver disease, diabetes mellitus, uncontrolled hypertension, renal disorders) history of, or planned surgery under general anesthesia from 1 year prior to the 1st study vaccination through the study period any other conditions which, in the opinion of the investigator, might interfere with the evaluation of the study objectives (e.g. neurologic or psychiatric conditions) female participants who are pregnant or breastfeeding current smokers or a recent smoking history within 12 weeks prior to the 1st study vaccination. occasional smokers who smoke up to 10 cigarettes per month may be allowed to participate at the investigator's discretion prior/concomitant therapy receipt of any medications or vaccinations intended to prevent covid-19. receipt of any vaccine within 4 weeks prior to the 1st study vaccination or planned receipt of any vaccine from enrollment through 28 days after the last study vaccination (visit 7), except for influenza vaccination, which may be received at least 2 weeks prior to the 1st study vaccination. this exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines receipt of immunoglobulins and/or any blood or blood products within 12 weeks prior to the 1st study vaccination chronic use (more than 2 consecutive weeks) of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy (≥10mg prednisone/day or equivalent for more than 2 consecutive weeks) within 12 weeks prior to the 1st vaccination. the use of topical and nasal glucocorticoids will be permitted. prior/concurrent clinical study experience participation in another clinical study involving study intervention within 6 months prior to the 1st study vaccination, or concurrent, planned participation in another clinical study with study intervention during this study period. other exclusions investigators, or study staff who are directly involved in the conduct of this study or supervised by the investigator, and their respective family members. healthcare worker or emergency response personnel in an occupation with a high risk of exposure to sars-cov-2

medical conditions 1. any clinically significant respiratory symptoms (e.g. cough, sore throat), febrile illness (tympanic temperature >38°c), or acute illness within 72 hours prior to the 1st study vaccination. a prospective participant should not be included until 72 hours after the condition has resolved. 2. history of virologically-confirmed covid-19 disease, or definite or suspected exposure to anyone known to have sars-cov-2 infection 3. history of virologically-confirmed sars or mers disease 4. history of congenital, hereditary, acquired immunodeficiency, or autoimmune disease 5. any positive test results for hepatitis b, c, or hiv at screening 6. history of bleeding disorder or thrombocytopenia which is contraindicating intramuscular vaccination in the investigator's opinion 7. history of hypersensitivity and severe allergic reaction (e.g. anaphylaxis, guillain-barre syndrome) to any vaccines or components of the study intervention 8. history of malignancy within 5 years prior to the 1st study vaccination 9. significant chronic illness that, in the opinion of the investigator, might increase risk of severe covid-19, or interfere with the evaluation of the study objectives (e.g. asthma, chronic pulmonary disease, cardiovascular disease, chronic liver disease, diabetes mellitus, uncontrolled hypertension, renal disorders) 10. history of, or planned surgery under general anesthesia from 1 year prior to the 1st study vaccination through the study period 11. any other conditions which, in the opinion of the investigator, might interfere with the evaluation of the study objectives (e.g. neurologic or psychiatric conditions) 12. female participants who are pregnant or breastfeeding 13. current smokers or a recent smoking history within 12 weeks prior to the 1st study vaccination. occasional smokers who smoke up to 10 cigarettes per month may be allowed to participate at the investigator's discretion prior/concomitant therapy 14. receipt of any medications or vaccinations intended to prevent covid-19. 15. receipt of any vaccine within 4 weeks prior to the 1st study vaccination or planned receipt of any vaccine from enrollment through 28 days after the last study vaccination (visit 7), except for influenza vaccination, which may be received at least 2 weeks prior to the 1st study vaccination. this exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines 16. receipt of immunoglobulins and/or any blood or blood products within 12 weeks prior to the 1st study vaccination 17. chronic use (more than 2 consecutive weeks) of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy (≥10mg prednisone/day or equivalent for more than 2 consecutive weeks) within 12 weeks prior to the 1st vaccination. the use of topical and nasal glucocorticoids will be permitted. prior/concurrent clinical study experience 18. participation in another clinical study involving study intervention within 6 months prior to the 1st study vaccination, or concurrent, planned participation in another clinical study with study intervention during this study period. other exclusions 19. investigators, or study staff who are directly involved in the conduct of this study or supervised by the investigator, and their respective family members. 20. healthcare worker or emergency response personnel in an occupation with a high risk of exposure to sars-cov-2

medical conditions 1. any clinically significant respiratory symptoms (e.g. cough, sore throat), febrile illness (tympanic temperature >38°c), or acute illness within 72 hours prior to the 1st study vaccination. a prospective participant should not be included until 72 hours after the condition has resolved. 2. history of virologically-confirmed covid-19 disease, or definite or suspected exposure to anyone known to have sars-cov-2 infection 3. history of virologically-confirmed sars or mers disease 4. history of congenital, hereditary, acquired immunodeficiency, or autoimmune disease 5. any positive test results for hepatitis b, c, or hiv at screening 6. history of bleeding disorder or thrombocytopenia which is contraindicating intramuscular vaccination in the investigator's opinion 7. history of hypersensitivity and severe allergic reaction (e.g. anaphylaxis, guillain-barre syndrome) to any vaccines or components of the study intervention 8. history of malignancy within 5 years prior to the 1st study vaccination 9. significant chronic illness that, in the opinion of the investigator, might increase risk of severe covid-19, or interfere with the evaluation of the study objectives (e.g. asthma, chronic pulmonary disease, cardiovascular disease, chronic liver disease, diabetes mellitus, uncontrolled hypertension, renal disorders) 10. history of, or planned surgery under general anesthesia from 1 year prior to the 1st study vaccination through the study period 11. any other conditions which, in the opinion of the investigator, might interfere with the evaluation of the study objectives (e.g. neurologic or psychiatric conditions) 12. female participants who are pregnant or breastfeeding 13. current smokers or a recent smoking history within 12 weeks prior to the 1st study vaccination. occasional smokers who smoke up to 10 cigarettes per month may be allowed to participate at the investigator's discretion prior/concomitant therapy 14. receipt of any medications or vaccinations intended to prevent covid-19. 15. receipt of any vaccine within 4 weeks prior to the 1st study vaccination or planned receipt of any vaccine from enrollment through 28 days after the last study vaccination (visit 7), except for influenza vaccination, which may be received at least 2 weeks prior to the 1st study vaccination. this exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines 16. receipt of immunoglobulins and/or any blood or blood products within 12 weeks prior to the 1st study vaccination 17. chronic use (more than 2 consecutive weeks) of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy (≥10mg prednisone/day or equivalent for more than 2 consecutive weeks) within 12 weeks prior to the 1st vaccination. the use of topical and nasal glucocorticoids will be permitted. prior/concurrent clinical study experience 18. participation in another clinical study involving study intervention within 6 months prior to the 1st study vaccination, or concurrent, planned participation in another clinical study with study intervention during this study period. other exclusions 19. investigators, or study staff who are directly involved in the conduct of this study or supervised by the investigator, and their respective family members. 20. healthcare worker or emergency response personnel in an occupation with a high risk of exposure to sars-cov-2