1. positive pregnancy test either at screening or just prior to each vaccine administration. 2. female subject who is breastfeeding or plans to breastfeed from the time of the first vaccination through 60 days after the last vaccination. 3. individuals at high risk for severe covid-19, including those with any of the following risk factors: 1. type 1 diabetes (t1d), or type 2 diabetes (t2d) that cannot be controlled by drugs 2. hypertension that cannot be controlled by drugs 3. current smoking 4. history of chronic smoking within the prior year 5. bmi is ≤ 18 kg/m2 or ≥ 40 kg/m2 6. resident in a long-term facility 4. have any other medical disease/condition or psychiatric condition that, in the opinion of the participating site principal investigator (pi) or appropriate sub-investigator, precludes study participation. (appendix ii) 5. history of recent covid-19 diagnosis; within 6 months prior to enrollment . this should be confirmed with chest computed tomography (ct) scan and or polymerase chain reaction (pcr). 6. has an acute illness, as determined by the participating site pi or appropriate sub-investigator, with or without fever (oral temperature of 37.8 °c or above) within 72 hours prior to each vaccination. an acute illness which is nearly resolved with only minor residual symptoms remaining is allowable if, in the opinion of the participating site pi or appropriate sub-investigator, the residual symptoms will not interfere with the ability to assess safety parameters as required by the protocol. 7. has a positive test result for hepatitis b surface antigen, hepatitis c virus antibody, or human immunodeficiency virus (hiv) types 1 or 2 antibodies at screening. 8. has participated in another investigational study involving any investigational product (study drug, biologic or device) within 60 days, or 5 half-lives, whichever is longer, before the first vaccine administration. 9. currently enrolled in or plans to participate in another clinical study with an investigational agent that will be received during the study-reporting period. 10. has a history of hypersensitivity or severe allergic reaction (e.g., anaphylaxis, generalized urticaria, angioedema, other significant reaction) to any previous licensed or unlicensed vaccines. 11. exposure to radiotherapy or chronic use (more than 14 continuous days) of any medications that may be associated with impaired immune responsiveness. including, but not limited to, systemic corticosteroids exceeding ≥20 mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar drugs during the preceding 6-month period prior to vaccine administration (day 0). the use of low dose topical, ophthalmic, inhaled and intranasal steroid preparations will be permitted. 12. anticipating the need for radiotherapy or immunosuppressive treatment within the next 6 months. including, but not limited to, systemic corticosteroids ≥20 mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar drugs during the preceding 6-month period prior to vaccine administration (day 0). the use of low dose topical, ophthalmic, inhaled and intranasal steroid preparations will be permitted. 13. received immunoglobulins and/or any blood or blood products within the 4 months before the first vaccine administration or at any time during the study. 14. has any blood dyscrasias or clinically significant disorder of coagulation (in the opinion of the investigator). the use of ≤325 mg of aspirin per day as prophylaxis is permitted, but the use of other platelet aggregation inhibitors, thrombin inhibitors, factor xa inhibitors, or warfarin derivatives is exclusionary, regardless of bleeding history. 15. has any liver disease or impairment, including fatty liver. 16. has a history of alcohol abuse or other recreational drug use within 6 months before the first vaccine administration. 17. has a positive test result for drugs of abuse at screening or before the first vaccine administration. 18. has any abnormality that would interfere with the ability to observe local reactions at the injection site. 19. received or plans to receive a licensed, live vaccine within 4 weeks before or after each vaccination. for example: yellow fever, tuberculosis (bcg), influenza live attenuated. 20. received or plans to receive a licensed, inactivated vaccine within 2 weeks before or after each vaccination. 21. receipt of any other sars-cov-2 or other experimental coronavirus vaccine at any time prior to or during the study. 22. close contact of anyone known to have sars-cov-2 infection within 30 days prior to vaccine administration. if exposure is suspected, subjects may be enrolled with subsequent documentation of a negative test for sars-cov-2, at the discretion of the investigator. 23. on current treatment with investigational agents for prophylaxis of covid-19. 24. currently working in occupations with high risk of exposure to sars-cov-2 (e.g., healthcare worker, emergency response personnel).

1. positive pregnancy test either at screening or just prior to each vaccine administration. 2. female subject who is breastfeeding or plans to breastfeed from the time of the first vaccination through 60 days after the last vaccination. 3. individuals at high risk for severe covid-19, including those with any of the following risk factors: 1. type 1 diabetes (t1d), or type 2 diabetes (t2d) that cannot be controlled by drugs 2. hypertension that cannot be controlled by drugs 3. current smoking 4. history of chronic smoking within the prior year 5. bmi is ≤ 18 kg/m2 or ≥ 40 kg/m2 6. resident in a long-term facility 4. have any other medical disease/condition or psychiatric condition that, in the opinion of the participating site principal investigator (pi) or appropriate sub-investigator, precludes study participation. (appendix ii) 5. history of recent covid-19 diagnosis; within 6 months prior to enrollment . this should be confirmed with chest computed tomography (ct) scan and or polymerase chain reaction (pcr). 6. has an acute illness, as determined by the participating site pi or appropriate sub-investigator, with or without fever (oral temperature of 37.8 °c or above) within 72 hours prior to each vaccination. an acute illness which is nearly resolved with only minor residual symptoms remaining is allowable if, in the opinion of the participating site pi or appropriate sub-investigator, the residual symptoms will not interfere with the ability to assess safety parameters as required by the protocol. 7. has a positive test result for hepatitis b surface antigen, hepatitis c virus antibody, or human immunodeficiency virus (hiv) types 1 or 2 antibodies at screening. 8. has participated in another investigational study involving any investigational product (study drug, biologic or device) within 60 days, or 5 half-lives, whichever is longer, before the first vaccine administration. 9. currently enrolled in or plans to participate in another clinical study with an investigational agent that will be received during the study-reporting period. 10. has a history of hypersensitivity or severe allergic reaction (e.g., anaphylaxis, generalized urticaria, angioedema, other significant reaction) to any previous licensed or unlicensed vaccines. 11. exposure to radiotherapy or chronic use (more than 14 continuous days) of any medications that may be associated with impaired immune responsiveness. including, but not limited to, systemic corticosteroids exceeding ≥20 mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar drugs during the preceding 6-month period prior to vaccine administration (day 0). the use of low dose topical, ophthalmic, inhaled and intranasal steroid preparations will be permitted. 12. anticipating the need for radiotherapy or immunosuppressive treatment within the next 6 months. including, but not limited to, systemic corticosteroids ≥20 mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar drugs during the preceding 6-month period prior to vaccine administration (day 0). the use of low dose topical, ophthalmic, inhaled and intranasal steroid preparations will be permitted. 13. received immunoglobulins and/or any blood or blood products within the 4 months before the first vaccine administration or at any time during the study. 14. has any blood dyscrasias or clinically significant disorder of coagulation (in the opinion of the investigator). the use of ≤325 mg of aspirin per day as prophylaxis is permitted, but the use of other platelet aggregation inhibitors, thrombin inhibitors, factor xa inhibitors, or warfarin derivatives is exclusionary, regardless of bleeding history. 15. has any liver disease or impairment, including fatty liver. 16. has a history of alcohol abuse or other recreational drug use within 6 months before the first vaccine administration. 17. has a positive test result for drugs of abuse at screening or before the first vaccine administration. 18. has any abnormality that would interfere with the ability to observe local reactions at the injection site. 19. received or plans to receive a licensed, live vaccine within 4 weeks before or after each vaccination. for example: yellow fever, tuberculosis (bcg), influenza live attenuated. 20. received or plans to receive a licensed, inactivated vaccine within 2 weeks before or after each vaccination. 21. receipt of any other sars-cov-2 or other experimental coronavirus vaccine at any time prior to or during the study. 22. close contact of anyone known to have sars-cov-2 infection within 30 days prior to vaccine administration. if exposure is suspected, subjects may be enrolled with subsequent documentation of a negative test for sars-cov-2, at the discretion of the investigator. 23. on current treatment with investigational agents for prophylaxis of covid-19. 24. currently working in occupations with high risk of exposure to sars-cov-2 (e.g., healthcare worker, emergency response personnel).

positive pregnancy test either at screening or just prior to each vaccine administration. female subject who is breastfeeding or plans to breastfeed from the time of the first vaccination through 60 days after the last vaccination. individuals at high risk for severe covid-19, including those with any of the following risk factors: type 1 diabetes (t1d), or type 2 diabetes (t2d) that cannot be controlled by drugs hypertension that cannot be controlled by drugs current smoking history of chronic smoking within the prior year bmi is ≤ 18 kg/m2 or ≥ 40 kg/m2 resident in a long-term facility have any other medical disease/condition or psychiatric condition that, in the opinion of the participating site principal investigator (pi) or appropriate sub-investigator, precludes study participation. (appendix ii) history of recent covid-19 diagnosis; within 6 months prior to enrollment . this should be confirmed with chest computed tomography (ct) scan and or polymerase chain reaction (pcr). has an acute illness, as determined by the participating site pi or appropriate sub-investigator, with or without fever (oral temperature of 37.8 °c or above) within 72 hours prior to each vaccination. an acute illness which is nearly resolved with only minor residual symptoms remaining is allowable if, in the opinion of the participating site pi or appropriate sub-investigator, the residual symptoms will not interfere with the ability to assess safety parameters as required by the protocol. has a positive test result for hepatitis b surface antigen, hepatitis c virus antibody, or human immunodeficiency virus (hiv) types 1 or 2 antibodies at screening. has participated in another investigational study involving any investigational product (study drug, biologic or device) within 60 days, or 5 half-lives, whichever is longer, before the first vaccine administration. currently enrolled in or plans to participate in another clinical study with an investigational agent that will be received during the study-reporting period. has a history of hypersensitivity or severe allergic reaction (e.g., anaphylaxis, generalized urticaria, angioedema, other significant reaction) to any previous licensed or unlicensed vaccines. exposure to radiotherapy or chronic use (more than 14 continuous days) of any medications that may be associated with impaired immune responsiveness. including, but not limited to, systemic corticosteroids exceeding ≥20 mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar drugs during the preceding 6-month period prior to vaccine administration (day 0). the use of low dose topical, ophthalmic, inhaled and intranasal steroid preparations will be permitted. anticipating the need for radiotherapy or immunosuppressive treatment within the next 6 months. including, but not limited to, systemic corticosteroids ≥20 mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar drugs during the preceding 6-month period prior to vaccine administration (day 0). the use of low dose topical, ophthalmic, inhaled and intranasal steroid preparations will be permitted. received immunoglobulins and/or any blood or blood products within the 4 months before the first vaccine administration or at any time during the study. has any blood dyscrasias or clinically significant disorder of coagulation (in the opinion of the investigator). the use of ≤325 mg of aspirin per day as prophylaxis is permitted, but the use of other platelet aggregation inhibitors, thrombin inhibitors, factor xa inhibitors, or warfarin derivatives is exclusionary, regardless of bleeding history. has any liver disease or impairment, including fatty liver. has a history of alcohol abuse or other recreational drug use within 6 months before the first vaccine administration. has a positive test result for drugs of abuse at screening or before the first vaccine administration. has any abnormality that would interfere with the ability to observe local reactions at the injection site. received or plans to receive a licensed, live vaccine within 4 weeks before or after each vaccination. for example: yellow fever, tuberculosis (bcg), influenza live attenuated. received or plans to receive a licensed, inactivated vaccine within 2 weeks before or after each vaccination. receipt of any other sars-cov-2 or other experimental coronavirus vaccine at any time prior to or during the study. close contact of anyone known to have sars-cov-2 infection within 30 days prior to vaccine administration. if exposure is suspected, subjects may be enrolled with subsequent documentation of a negative test for sars-cov-2, at the discretion of the investigator. on current treatment with investigational agents for prophylaxis of covid-19. currently working in occupations with high risk of exposure to sars-cov-2 (e.g., healthcare worker, emergency response personnel).

positive pregnancy test either at screening or just prior to each vaccine administration. female subject who is breastfeeding or plans to breastfeed from the time of the first vaccination through 60 days after the last vaccination. individuals at high risk for severe covid-19, including those with any of the following risk factors: type 1 diabetes (t1d), or type 2 diabetes (t2d) that cannot be controlled by drugs hypertension that cannot be controlled by drugs current smoking history of chronic smoking within the prior year bmi is ≤ 18 kg/m2 or ≥ 40 kg/m2 resident in a long-term facility have any other medical disease/condition or psychiatric condition that, in the opinion of the participating site principal investigator (pi) or appropriate sub-investigator, precludes study participation. (appendix ii) history of recent covid-19 diagnosis; within 6 months prior to enrollment . this should be confirmed with chest computed tomography (ct) scan and or polymerase chain reaction (pcr). has an acute illness, as determined by the participating site pi or appropriate sub-investigator, with or without fever (oral temperature of 37.8 °c or above) within 72 hours prior to each vaccination. an acute illness which is nearly resolved with only minor residual symptoms remaining is allowable if, in the opinion of the participating site pi or appropriate sub-investigator, the residual symptoms will not interfere with the ability to assess safety parameters as required by the protocol. has a positive test result for hepatitis b surface antigen, hepatitis c virus antibody, or human immunodeficiency virus (hiv) types 1 or 2 antibodies at screening. has participated in another investigational study involving any investigational product (study drug, biologic or device) within 60 days, or 5 half-lives, whichever is longer, before the first vaccine administration. currently enrolled in or plans to participate in another clinical study with an investigational agent that will be received during the study-reporting period. has a history of hypersensitivity or severe allergic reaction (e.g., anaphylaxis, generalized urticaria, angioedema, other significant reaction) to any previous licensed or unlicensed vaccines. exposure to radiotherapy or chronic use (more than 14 continuous days) of any medications that may be associated with impaired immune responsiveness. including, but not limited to, systemic corticosteroids exceeding ≥20 mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar drugs during the preceding 6-month period prior to vaccine administration (day 0). the use of low dose topical, ophthalmic, inhaled and intranasal steroid preparations will be permitted. anticipating the need for radiotherapy or immunosuppressive treatment within the next 6 months. including, but not limited to, systemic corticosteroids ≥20 mg/day of prednisone equivalent, allergy injections, immunoglobulin, interferon, immunomodulators, cytotoxic drugs, or other similar drugs during the preceding 6-month period prior to vaccine administration (day 0). the use of low dose topical, ophthalmic, inhaled and intranasal steroid preparations will be permitted. received immunoglobulins and/or any blood or blood products within the 4 months before the first vaccine administration or at any time during the study. has any blood dyscrasias or clinically significant disorder of coagulation (in the opinion of the investigator). the use of ≤325 mg of aspirin per day as prophylaxis is permitted, but the use of other platelet aggregation inhibitors, thrombin inhibitors, factor xa inhibitors, or warfarin derivatives is exclusionary, regardless of bleeding history. has any liver disease or impairment, including fatty liver. has a history of alcohol abuse or other recreational drug use within 6 months before the first vaccine administration. has a positive test result for drugs of abuse at screening or before the first vaccine administration. has any abnormality that would interfere with the ability to observe local reactions at the injection site. received or plans to receive a licensed, live vaccine within 4 weeks before or after each vaccination. for example: yellow fever, tuberculosis (bcg), influenza live attenuated. received or plans to receive a licensed, inactivated vaccine within 2 weeks before or after each vaccination. receipt of any other sars-cov-2 or other experimental coronavirus vaccine at any time prior to or during the study. close contact of anyone known to have sars-cov-2 infection within 30 days prior to vaccine administration. if exposure is suspected, subjects may be enrolled with subsequent documentation of a negative test for sars-cov-2, at the discretion of the investigator. on current treatment with investigational agents for prophylaxis of covid-19. currently working in occupations with high risk of exposure to sars-cov-2 (e.g., healthcare worker, emergency response personnel).