* any ongoing, symptomatic acute or chronic illness requiring medical or surgical care, inclusive of changes in medication in the past 2 months (at the discretion of the investigator). this includes any current workup of undiagnosed illness that could lead to a new condition, including but not limited to any of the following conditions that are risk factors of severe illness from the virus that causes covid-19: * active cancer (malignancy) within 5 years prior to first study vaccination (with the exception of adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) * chronic kidney disease * copd * moderate to severe asthma * current tobacco smoking * people who have had an organ transplant. * heart conditions, such as heart failure, coronary artery disease, or cardiomyopathies * bmi ≥ 30 kg/m2 or bmi \<17 kg/m2 * type 2 diabetes mellitus * chronic liver disease * sickle cell disease hypertension * type 1 diabetes * known infection with human immunodeficiency virus (hiv), hepatitis c virus (hcv), or hepatitis b virus (hbv). * participation in research involving an investigational product (drug/biologic/device) within 45 days prior to first study vaccination. * history of a confirmed diagnosis of sars, mers or covid-19 disease (confirmed by a specific test for each disease) or known exposure during 2-4 weeks prior to enrollment to a sars-cov-2 positive confirmed close contact (eg, family member, housemate, daycare provider, aged parent requiring care), at the discretion of the investigator. * professionals involved in direct care of the covid-19 patients and with a high risk of exposure to sars-cov-2 (i.e., healthcare worker of intensive care unit at infectology department ). * currently taking any product (investigational or off-label) for prevention of covid-19 disease. * positive rapid test for sars-cov-2 (elisa or pcr) at screening or prior to first vaccination. * received influenza vaccination within 14 days prior to first study vaccination, or any other vaccine within 4 weeks prior to first study vaccination. note: covid-19 marketed vaccines may be allowed as long inclusion criterion #3 is met. * any autoimmune or immunodeficiency disease/condition (iatrogenic or congenital). * chronic administration (defined as more than 14 continuous days) of immunosuppressant, systemic glucocorticosteroids, or other immune-modifying drugs within 4 months prior to first study vaccination or anticipation of the need for immunosuppressive treatment within 6 months after last vaccination. * received immunoglobulin, blood-derived products, or other immunosuppressant drugs within 90 days prior to first study vaccination. * any acute illness concurrent or within 14 days prior to first study vaccination (medical history and/or physical examination) or documented temperature of ≥38°c during this period. this includes respiratory or constitutional symptoms consistent with sars-cov-2 (covid-19) (ie, cough, sore throat, difficulty breathing) * known disturbance of coagulation (iatrogenic or congenital). note: 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, because these imply treatment or prophylaxis of known cardiac or vascular disease. * any neurological disease or history of significant neurological disorder (eg, meningitis, seizures, multiple sclerosis, vasculitis, migraines, guillain-barré syndrome \[genetic/congenital or acquired\]). * vital sign (blood pressure, pulse, temperature) abnormalities of toxicity grade \>1 * clinical laboratory abnormalities of toxicity grade \>1 for selected serum chemistry and hematology parameters * any known allergies to products contained in the investigational product or latex allergy, or history of severe allergic reaction (e.g., swelling of the mouth and throat, difficulty breathing, hypotension, or shock) that required medical intervention. * women who are pregnant, breastfeeding or who plan to become pregnant during the study. * history of alcohol abuse or drug addiction within one year prior to the first study vaccination. * any condition that, in the opinion of the investigator, would pose a health risk to the subject if enrolled or could interfere with evaluation of the study vaccine or interpretation of study results (including neurologic or psychiatric conditions deemed likely to impair the quality of safety reporting). * study team member or first-degree relative of any study team member (inclusive of sponsor or delegate, and site personnel involved in the study).

* any ongoing, symptomatic acute or chronic illness requiring medical or surgical care, inclusive of changes in medication in the past 2 months (at the discretion of the investigator). this includes any current workup of undiagnosed illness that could lead to a new condition, including but not limited to any of the following conditions that are risk factors of severe illness from the virus that causes covid-19: * active cancer (malignancy) within 5 years prior to first study vaccination (with the exception of adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) * chronic kidney disease * copd * moderate to severe asthma * current tobacco smoking * people who have had an organ transplant. * heart conditions, such as heart failure, coronary artery disease, or cardiomyopathies * bmi ≥ 30 kg/m2 or bmi \<17 kg/m2 * type 2 diabetes mellitus * chronic liver disease * sickle cell disease hypertension * type 1 diabetes * known infection with human immunodeficiency virus (hiv), hepatitis c virus (hcv), or hepatitis b virus (hbv). * participation in research involving an investigational product (drug/biologic/device) within 45 days prior to first study vaccination. * history of a confirmed diagnosis of sars, mers or covid-19 disease (confirmed by a specific test for each disease) or known exposure during 2-4 weeks prior to enrollment to a sars-cov-2 positive confirmed close contact (eg, family member, housemate, daycare provider, aged parent requiring care), at the discretion of the investigator. * professionals involved in direct care of the covid-19 patients and with a high risk of exposure to sars-cov-2 (i.e., healthcare worker of intensive care unit at infectology department ). * currently taking any product (investigational or off-label) for prevention of covid-19 disease. * positive rapid test for sars-cov-2 (elisa or pcr) at screening or prior to first vaccination. * received influenza vaccination within 14 days prior to first study vaccination, or any other vaccine within 4 weeks prior to first study vaccination. note: covid-19 marketed vaccines may be allowed as long inclusion criterion #3 is met. * any autoimmune or immunodeficiency disease/condition (iatrogenic or congenital). * chronic administration (defined as more than 14 continuous days) of immunosuppressant, systemic glucocorticosteroids, or other immune-modifying drugs within 4 months prior to first study vaccination or anticipation of the need for immunosuppressive treatment within 6 months after last vaccination. * received immunoglobulin, blood-derived products, or other immunosuppressant drugs within 90 days prior to first study vaccination. * any acute illness concurrent or within 14 days prior to first study vaccination (medical history and/or physical examination) or documented temperature of ≥38°c during this period. this includes respiratory or constitutional symptoms consistent with sars-cov-2 (covid-19) (ie, cough, sore throat, difficulty breathing) * known disturbance of coagulation (iatrogenic or congenital). note: 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, because these imply treatment or prophylaxis of known cardiac or vascular disease. * any neurological disease or history of significant neurological disorder (eg, meningitis, seizures, multiple sclerosis, vasculitis, migraines, guillain-barré syndrome \[genetic/congenital or acquired\]). * vital sign (blood pressure, pulse, temperature) abnormalities of toxicity grade \>1 * clinical laboratory abnormalities of toxicity grade \>1 for selected serum chemistry and hematology parameters * any known allergies to products contained in the investigational product or latex allergy, or history of severe allergic reaction (e.g., swelling of the mouth and throat, difficulty breathing, hypotension, or shock) that required medical intervention. * women who are pregnant, breastfeeding or who plan to become pregnant during the study. * history of alcohol abuse or drug addiction within one year prior to the first study vaccination. * any condition that, in the opinion of the investigator, would pose a health risk to the subject if enrolled or could interfere with evaluation of the study vaccine or interpretation of study results (including neurologic or psychiatric conditions deemed likely to impair the quality of safety reporting). * study team member or first-degree relative of any study team member (inclusive of sponsor or delegate, and site personnel involved in the study).

- any ongoing, symptomatic acute or chronic illness requiring medical or surgical care, inclusive of changes in medication in the past 2 months (at the discretion of the investigator). this includes any current workup of undiagnosed illness that could lead to a new condition, including but not limited to any of the following conditions that are risk factors of severe illness from the virus that causes covid-19: - active cancer (malignancy) within 5 years prior to first study vaccination (with the exception of adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) - chronic kidney disease - copd - moderate to severe asthma - current tobacco smoking - people who have had an organ transplant. - heart conditions, such as heart failure, coronary artery disease, or cardiomyopathies - bmi ≥ 30 kg/m2 or bmi <17 kg/m2 - type 2 diabetes mellitus - chronic liver disease - sickle cell disease hypertension - type 1 diabetes - known infection with human immunodeficiency virus (hiv), hepatitis c virus (hcv), or hepatitis b virus (hbv). - participation in research involving an investigational product (drug/biologic/device) within 45 days prior to first study vaccination. - history of a confirmed diagnosis of sars, mers or covid-19 disease (confirmed by a specific test for each disease) or known exposure during 2-4 weeks prior to enrollment to a sars-cov-2 positive confirmed close contact (eg, family member, housemate, daycare provider, aged parent requiring care), at the discretion of the investigator. - professionals involved in direct care of the covid-19 patients and with a high risk of exposure to sars-cov-2 (i.e., healthcare worker of intensive care unit at infectology department ). - currently taking any product (investigational or off-label) for prevention of covid-19 disease. - positive rapid test for sars-cov-2 (elisa or pcr) at screening or prior to first vaccination. - received influenza vaccination within 14 days prior to first study vaccination, or any other vaccine within 4 weeks prior to first study vaccination. note: covid-19 marketed vaccines may be allowed as long inclusion criterion #3 is met. - any autoimmune or immunodeficiency disease/condition (iatrogenic or congenital). - chronic administration (defined as more than 14 continuous days) of immunosuppressant, systemic glucocorticosteroids, or other immune-modifying drugs within 4 months prior to first study vaccination or anticipation of the need for immunosuppressive treatment within 6 months after last vaccination. - received immunoglobulin, blood-derived products, or other immunosuppressant drugs within 90 days prior to first study vaccination. - any acute illness concurrent or within 14 days prior to first study vaccination (medical history and/or physical examination) or documented temperature of ≥38°c during this period. this includes respiratory or constitutional symptoms consistent with sars-cov-2 (covid-19) (ie, cough, sore throat, difficulty breathing) - known disturbance of coagulation (iatrogenic or congenital). note: 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, because these imply treatment or prophylaxis of known cardiac or vascular disease. - any neurological disease or history of significant neurological disorder (eg, meningitis, seizures, multiple sclerosis, vasculitis, migraines, guillain-barré syndrome [genetic/congenital or acquired]). - vital sign (blood pressure, pulse, temperature) abnormalities of toxicity grade >1 - clinical laboratory abnormalities of toxicity grade >1 for selected serum chemistry and hematology parameters - any known allergies to products contained in the investigational product or latex allergy, or history of severe allergic reaction (e.g., swelling of the mouth and throat, difficulty breathing, hypotension, or shock) that required medical intervention. - women who are pregnant, breastfeeding or who plan to become pregnant during the study. - history of alcohol abuse or drug addiction within one year prior to the first study vaccination. - any condition that, in the opinion of the investigator, would pose a health risk to the subject if enrolled or could interfere with evaluation of the study vaccine or interpretation of study results (including neurologic or psychiatric conditions deemed likely to impair the quality of safety reporting). - study team member or first-degree relative of any study team member (inclusive of sponsor or delegate, and site personnel involved in the study).

- any ongoing, symptomatic acute or chronic illness requiring medical or surgical care, inclusive of changes in medication in the past 2 months (at the discretion of the investigator). this includes any current workup of undiagnosed illness that could lead to a new condition, including but not limited to any of the following conditions that are risk factors of severe illness from the virus that causes covid-19: - active cancer (malignancy) within 5 years prior to first study vaccination (with the exception of adequately treated non-melanomatous skin carcinoma, at the discretion of the investigator) - chronic kidney disease - copd - moderate to severe asthma - current tobacco smoking - people who have had an organ transplant. - heart conditions, such as heart failure, coronary artery disease, or cardiomyopathies - bmi ≥ 30 kg/m2 or bmi <17 kg/m2 - type 2 diabetes mellitus - chronic liver disease - sickle cell disease hypertension - type 1 diabetes - known infection with human immunodeficiency virus (hiv), hepatitis c virus (hcv), or hepatitis b virus (hbv). - participation in research involving an investigational product (drug/biologic/device) within 45 days prior to first study vaccination. - history of a confirmed diagnosis of sars, mers or covid-19 disease (confirmed by a specific test for each disease) or known exposure during 2-4 weeks prior to enrollment to a sars-cov-2 positive confirmed close contact (eg, family member, housemate, daycare provider, aged parent requiring care), at the discretion of the investigator. - professionals involved in direct care of the covid-19 patients and with a high risk of exposure to sars-cov-2 (i.e., healthcare worker of intensive care unit at infectology department ). - currently taking any product (investigational or off-label) for prevention of covid-19 disease. - positive rapid test for sars-cov-2 (elisa or pcr) at screening or prior to first vaccination. - received influenza vaccination within 14 days prior to first study vaccination, or any other vaccine within 4 weeks prior to first study vaccination. note: covid-19 marketed vaccines may be allowed as long inclusion criterion #3 is met. - any autoimmune or immunodeficiency disease/condition (iatrogenic or congenital). - chronic administration (defined as more than 14 continuous days) of immunosuppressant, systemic glucocorticosteroids, or other immune-modifying drugs within 4 months prior to first study vaccination or anticipation of the need for immunosuppressive treatment within 6 months after last vaccination. - received immunoglobulin, blood-derived products, or other immunosuppressant drugs within 90 days prior to first study vaccination. - any acute illness concurrent or within 14 days prior to first study vaccination (medical history and/or physical examination) or documented temperature of ≥38°c during this period. this includes respiratory or constitutional symptoms consistent with sars-cov-2 (covid-19) (ie, cough, sore throat, difficulty breathing) - known disturbance of coagulation (iatrogenic or congenital). note: 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, because these imply treatment or prophylaxis of known cardiac or vascular disease. - any neurological disease or history of significant neurological disorder (eg, meningitis, seizures, multiple sclerosis, vasculitis, migraines, guillain-barré syndrome [genetic/congenital or acquired]). - vital sign (blood pressure, pulse, temperature) abnormalities of toxicity grade >1 - clinical laboratory abnormalities of toxicity grade >1 for selected serum chemistry and hematology parameters - any known allergies to products contained in the investigational product or latex allergy, or history of severe allergic reaction (e.g., swelling of the mouth and throat, difficulty breathing, hypotension, or shock) that required medical intervention. - women who are pregnant, breastfeeding or who plan to become pregnant during the study. - history of alcohol abuse or drug addiction within one year prior to the first study vaccination. - any condition that, in the opinion of the investigator, would pose a health risk to the subject if enrolled or could interfere with evaluation of the study vaccine or interpretation of study results (including neurologic or psychiatric conditions deemed likely to impair the quality of safety reporting). - study team member or first-degree relative of any study team member (inclusive of sponsor or delegate, and site personnel involved in the study).