1. Participant has a clinically significant acute illness (this does not include minor illnesses such as diarrhea or mild upper respiratory tract infection) or temperature ≥38.0ºC (100.4°F) within 24 hours prior to the planned first dose of study vaccine, randomization at a later date is permitted at the discretion of the investigator and after consultation with the sponsor. 2. Participant has a history of malignancy within 5 years before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or malignancy, which is considered cured with minimal risk of recurrence). 3. Participant has a known or suspected allergy or history of anaphylaxis or other serious adverse reactions to vaccines or their excipients (including specifically the excipients of the study vaccine). 4. Participant has abnormal function of the immune system. 5. Participant has a history of any neurological disorders or seizures including Guillain-Barré syndrome, with the exception of febrile seizures during childhood. 6. Participant has a history of chronic urticaria (recurrent hives), eczema or adult atopic dermatitis. 7. Participant received treatment with immunoglobulins in the 3 months or blood products in the 4 months before the planned administration of the first dose of study vaccine or has any plans to receive such treatment during the study. 8. Participant is a woman who is pregnant, breastfeeding, or planning to become pregnant while enrolled in this study or within 3 months after the last dose of study vaccine. 9. Participant has chronic active hepatitis B or hepatitis C infection per medical history. 10. Participant previously received a coronavirus vaccine. 11. Participant has a positive diagnostic test result for past (serological testing) or current (PCR based viral RNA detection) SARS-CoV-2 infection at screening. 12. Participants with comorbidities that are or might be associated with an increased risk of progression to severe COVID-19, ie, participants with moderate-to severe asthma, chronic lung diseases such as chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), idiopathic pulmonary fibrosis and cystic fibrosis, diabetes (including type 1, type 2, or gestational), serious heart conditions, including heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, and pulmonary hypertension or high blood pressure, obesity (BMI ≥ 30 kg/m2), chronic liver disease, including cirrhosis, sickle cell disease, thalassemia, cerebrovascular disease, neurologic conditions (dementia), and participants who live in nursing homes or long-term care facilities. This list is consistent with the list of conditions that increase the risk of progression to severe COVID-19 available at the CDC website at the time of writing of this protocol, except for smoking, which is allowed. 13. Participant who is currently working in an occupation with a high risk of exposure to SARS-CoV-2 infection (eg, health care worker or emergency response personnel who work in close contact with SARS-CoV-2 infected patients) or considered at the investigator’s discretion to be at increased risk to acquire COVID-19 for any other reason. 14. Participant who has had a known exposure to an individual with confirmed COVID-19 or SARS-CoV-2 infection within the past 2 weeks. 15. History of confirmed SARS or MERS.

1. Participant has a clinically significant acute illness (this does not include minor illnesses such as diarrhea or mild upper respiratory tract infection) or temperature ≥38.0ºC (100.4°F) within 24 hours prior to the planned first dose of study vaccine, randomization at a later date is permitted at the discretion of the investigator and after consultation with the sponsor. 2. Participant has a history of malignancy within 5 years before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or malignancy, which is considered cured with minimal risk of recurrence). 3. Participant has a known or suspected allergy or history of anaphylaxis or other serious adverse reactions to vaccines or their excipients (including specifically the excipients of the study vaccine). 4. Participant has abnormal function of the immune system. 5. Participant has a history of any neurological disorders or seizures including Guillain-Barré syndrome, with the exception of febrile seizures during childhood. 6. Participant has a history of chronic urticaria (recurrent hives), eczema or adult atopic dermatitis. 7. Participant received treatment with immunoglobulins in the 3 months or blood products in the 4 months before the planned administration of the first dose of study vaccine or has any plans to receive such treatment during the study. 8. Participant is a woman who is pregnant, breastfeeding, or planning to become pregnant while enrolled in this study or within 3 months after the last dose of study vaccine. 9. Participant has chronic active hepatitis B or hepatitis C infection per medical history. 10. Participant previously received a coronavirus vaccine. 11. Participant has a positive diagnostic test result for past (serological testing) or current (PCR based viral RNA detection) SARS-CoV-2 infection at screening. 12. Participants with comorbidities that are or might be associated with an increased risk of progression to severe COVID-19, ie, participants with moderate-to severe asthma, chronic lung diseases such as chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), idiopathic pulmonary fibrosis and cystic fibrosis, diabetes (including type 1, type 2, or gestational), serious heart conditions, including heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, and pulmonary hypertension or high blood pressure, obesity (BMI ≥ 30 kg/m2), chronic liver disease, including cirrhosis, sickle cell disease, thalassemia, cerebrovascular disease, neurologic conditions (dementia), and participants who live in nursing homes or long-term care facilities. This list is consistent with the list of conditions that increase the risk of progression to severe COVID-19 available at the CDC website at the time of writing of this protocol, except for smoking, which is allowed. 13. Participant who is currently working in an occupation with a high risk of exposure to SARS-CoV-2 infection (eg, health care worker or emergency response personnel who work in close contact with SARS-CoV-2 infected patients) or considered at the investigator’s discretion to be at increased risk to acquire COVID-19 for any other reason. 14. Participant who has had a known exposure to an individual with confirmed COVID-19 or SARS-CoV-2 infection within the past 2 weeks. 15. History of confirmed SARS or MERS.

1. Participant has a clinically significant acute illness (this does not include minor illnesses such as diarrhea or mild upper respiratory tract infection) or temperature ≥38.0ºC (100.4°F) within 24 hours prior to the planned first dose of study vaccine, randomization at a later date is permitted at the discretion of the investigator and after consultation with the sponsor. 2. Participant has a history of malignancy within 5 years before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or malignancy, which is considered cured with minimal risk of recurrence). 3. Participant has a known or suspected allergy or history of anaphylaxis or other serious adverse reactions to vaccines or their excipients (including specifically the excipients of the study vaccine). 4. Participant has abnormal function of the immune system. 5. Participant has a history of any neurological disorders or seizures including Guillain-Barré syndrome, with the exception of febrile seizures during childhood. 6. Participant has a history of chronic urticaria (recurrent hives), eczema or adult atopic dermatitis. 7. Participant received treatment with immunoglobulins in the 3 months or blood products in the 4 months before the planned administration of the first dose of study vaccine or has any plans to receive such treatment during the study. 8. Participant is a woman who is pregnant, breastfeeding, or planning to become pregnant within 3 months after the last dose of study vaccine. 9. Participant has chronic active hepatitis B or hepatitis C infection per medical history. 10. Participant previously received a coronavirus vaccine. 11. Participant has a positive diagnostic test result for past (serological testing) or current (PCR based viral RNA detection) SARS-CoV-2 infection at screening. 12. Participants with comorbidities that are or might be associated with an increased risk of progression to severe COVID-19, ie, participants with moderate-to severe asthma, chronic lung diseases such as chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), idiopathic pulmonary fibrosis and cystic fibrosis, diabetes (including type 1, type 2), serious heart conditions, including heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, and pulmonary hypertension or high blood pressure, obesity (BMI ≥ 30 kg/m2), chronic liver disease, including cirrhosis, sickle cell disease, thalassemia, cerebrovascular disease, neurologic conditions (dementia), end stage renal disease, organ transplantation, cancer, HIV infection and other immunodeficiencies,hepatitis B infection, and sleep apnea. This list is consistent with the list of conditions that increase the risk of progression to severe COVID-19 available at the CDC website at the time of writing of this protocol, except for smoking, which is allowed. Applicable only to participants 65 years of age and older: Participants may have hypertension of mild severity as long as it is stable and medically controlled as defined by no change in medication over the past 6 months (except for issues of tolerability or use of similar drug with same mechanism of action, eg, thiazides, Beta blockers, Alpha blockers at the same effective dose). 13. Participant who is currently working in an occupation with a high risk of exposure to SARS-CoV-2 infection (eg, health care worker or emergency response personnel who work in close contact with SARS-CoV-2 infected patients) or considered at the investigator’s discretion to be at increased risk to acquire COVID-19 for any other reason. 14. Participant who has had a known exposure to an individual with confirmed COVID-19 or SARS-CoV-2 infection within the past 2 weeks. 15. History of confirmed SARS or MERS. Please refer to the protocol for more info

1. Participant has a clinically significant acute illness (this does not include minor illnesses such as diarrhea or mild upper respiratory tract infection) or temperature ≥38.0ºC (100.4°F) within 24 hours prior to the planned first dose of study vaccine, randomization at a later date is permitted at the discretion of the investigator and after consultation with the sponsor. 2. Participant has a history of malignancy within 5 years before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or malignancy, which is considered cured with minimal risk of recurrence). 3. Participant has a known or suspected allergy or history of anaphylaxis or other serious adverse reactions to vaccines or their excipients (including specifically the excipients of the study vaccine). 4. Participant has abnormal function of the immune system. 5. Participant has a history of any neurological disorders or seizures including Guillain-Barré syndrome, with the exception of febrile seizures during childhood. 6. Participant has a history of chronic urticaria (recurrent hives), eczema or adult atopic dermatitis. 7. Participant received treatment with immunoglobulins in the 3 months or blood products in the 4 months before the planned administration of the first dose of study vaccine or has any plans to receive such treatment during the study. 8. Participant is a woman who is pregnant, breastfeeding, or planning to become pregnant within 3 months after the last dose of study vaccine. 9. Participant has chronic active hepatitis B or hepatitis C infection per medical history. 10. Participant previously received a coronavirus vaccine. 11. Participant has a positive diagnostic test result for past (serological testing) or current (PCR based viral RNA detection) SARS-CoV-2 infection at screening. 12. Participants with comorbidities that are or might be associated with an increased risk of progression to severe COVID-19, ie, participants with moderate-to severe asthma, chronic lung diseases such as chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), idiopathic pulmonary fibrosis and cystic fibrosis, diabetes (including type 1, type 2), serious heart conditions, including heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, and pulmonary hypertension or high blood pressure, obesity (BMI ≥ 30 kg/m2), chronic liver disease, including cirrhosis, sickle cell disease, thalassemia, cerebrovascular disease, neurologic conditions (dementia), end stage renal disease, organ transplantation, cancer, HIV infection and other immunodeficiencies,hepatitis B infection, and sleep apnea. This list is consistent with the list of conditions that increase the risk of progression to severe COVID-19 available at the CDC website at the time of writing of this protocol, except for smoking, which is allowed. Applicable only to participants 65 years of age and older: Participants may have hypertension of mild severity as long as it is stable and medically controlled as defined by no change in medication over the past 6 months (except for issues of tolerability or use of similar drug with same mechanism of action, eg, thiazides, Beta blockers, Alpha blockers at the same effective dose). 13. Participant who is currently working in an occupation with a high risk of exposure to SARS-CoV-2 infection (eg, health care worker or emergency response personnel who work in close contact with SARS-CoV-2 infected patients) or considered at the investigator’s discretion to be at increased risk to acquire COVID-19 for any other reason. 14. Participant who has had a known exposure to an individual with confirmed COVID-19 or SARS-CoV-2 infection within the past 2 weeks. 15. History of confirmed SARS or MERS. Please refer to the protocol for more info

1. Participant has a clinically significant acute illness (this does not include minor illnesses such as diarrhea or mild upper respiratory tract infection) or temperature ≥38.0ºC (100.4°F) within 24 hours prior to the planned first dose of study vaccine, randomization at a later date is permitted at the discretion of the investigator and after consultation with the sponsor. 2. Participant has a history of malignancy within 5 years before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or malignancy, which is considered cured with minimal risk of recurrence). 3. Participant has a known or suspected allergy or history of anaphylaxis or other serious adverse reactions to vaccines or their excipients (including specifically the excipients of the study vaccine). 4. Participant has abnormal function of the immune system. 5. Participant has a history of any neurological disorders or seizures including Guillain-Barré syndrome, with the exception of febrile seizures during childhood. 6. Participant has a history of chronic urticaria (recurrent hives), eczema or adult atopic dermatitis. 7. Participant received treatment with immunoglobulins in the 3 months or blood products in the 4 months before the planned administration of the first dose of study vaccine or has any plans to receive such treatment during the study. 8. Participant is a woman who is pregnant, breastfeeding, or planning to become pregnant while enrolled in this study or within 3 months after the last dose of study vaccine. 9. Participant has chronic active hepatitis B or hepatitis C infection per medical history. 10. Participant previously received a coronavirus vaccine. 11. Participant has a positive diagnostic test result for past (serological testing) or current (PCR based viral RNA detection) SARS-CoV-2 infection at screening. 12. Participants with comorbidities that are or might be associated with an increased risk of progression to severe COVID-19, ie, participants with moderate-to severe asthma, chronic lung diseases such as chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), idiopathic pulmonary fibrosis and cystic fibrosis, diabetes (including type 1, type 2, or gestational), serious heart conditions, including heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, and pulmonary hypertension or high blood pressure, obesity (BMI ≥ 30 kg/m2), chronic liver disease, including cirrhosis, sickle cell disease, thalassemia, cerebrovascular disease, neurologic conditions (dementia), and participants who live in nursing homes or long-term care facilities. This list is consistent with the list of conditions that increase the risk of progression to severe COVID-19 available at the CDC website at the time of writing of this protocol, except for smoking, which is allowed. 13. Participant who is currently working in an occupation with a high risk of exposure to SARS-CoV-2 infection (eg, health care worker or emergency response personnel who work in close contact with SARS-CoV-2 infected patients) or considered at the investigator’s discretion to be at increased risk to acquire COVID-19 for any other reason. 14. Participant who has had a known exposure to an individual with confirmed COVID-19 or SARS-CoV-2 infection within the past 2 weeks. 15. History of confirmed SARS or MERS.

1. Participant has a clinically significant acute illness (this does not include minor illnesses such as diarrhea or mild upper respiratory tract infection) or temperature ≥38.0ºC (100.4°F) within 24 hours prior to the planned first dose of study vaccine, randomization at a later date is permitted at the discretion of the investigator and after consultation with the sponsor. 2. Participant has a history of malignancy within 5 years before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or malignancy, which is considered cured with minimal risk of recurrence). 3. Participant has a known or suspected allergy or history of anaphylaxis or other serious adverse reactions to vaccines or their excipients (including specifically the excipients of the study vaccine). 4. Participant has abnormal function of the immune system. 5. Participant has a history of any neurological disorders or seizures including Guillain-Barré syndrome, with the exception of febrile seizures during childhood. 6. Participant has a history of chronic urticaria (recurrent hives), eczema or adult atopic dermatitis. 7. Participant received treatment with immunoglobulins in the 3 months or blood products in the 4 months before the planned administration of the first dose of study vaccine or has any plans to receive such treatment during the study. 8. Participant is a woman who is pregnant, breastfeeding, or planning to become pregnant while enrolled in this study or within 3 months after the last dose of study vaccine. 9. Participant has chronic active hepatitis B or hepatitis C infection per medical history. 10. Participant previously received a coronavirus vaccine. 11. Participant has a positive diagnostic test result for past (serological testing) or current (PCR based viral RNA detection) SARS-CoV-2 infection at screening. 12. Participants with comorbidities that are or might be associated with an increased risk of progression to severe COVID-19, ie, participants with moderate-to severe asthma, chronic lung diseases such as chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), idiopathic pulmonary fibrosis and cystic fibrosis, diabetes (including type 1, type 2, or gestational), serious heart conditions, including heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, and pulmonary hypertension or high blood pressure, obesity (BMI ≥ 30 kg/m2), chronic liver disease, including cirrhosis, sickle cell disease, thalassemia, cerebrovascular disease, neurologic conditions (dementia), and participants who live in nursing homes or long-term care facilities. This list is consistent with the list of conditions that increase the risk of progression to severe COVID-19 available at the CDC website at the time of writing of this protocol, except for smoking, which is allowed. 13. Participant who is currently working in an occupation with a high risk of exposure to SARS-CoV-2 infection (eg, health care worker or emergency response personnel who work in close contact with SARS-CoV-2 infected patients) or considered at the investigator’s discretion to be at increased risk to acquire COVID-19 for any other reason. 14. Participant who has had a known exposure to an individual with confirmed COVID-19 or SARS-CoV-2 infection within the past 2 weeks. 15. History of confirmed SARS or MERS.