1. history of covid-19 illness of moderate or greater severity, defined as one of the following: 1. moderate illness: individuals who show evidence of lower respiratory disease during clinical assessment or imaging and who have an oxygen saturation (spo2) ≥94% on room air at sea level. 2. severe covid-19 illness: individuals who have spo2 \<94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) \<300 mm hg, a respiratory rate \>30 breaths/min, or lung infiltrates \>50%. 3. critical covid-19 illness: individuals who have respiratory failure, septic shock, and/or multiple organ dysfunction. 2. positive sars-cov-2 pcr or rapid antigen test at screening. 3. history of sars or mers. 4. participant with a history of an underlying clinically significant acute or chronic medical condition or physical examination findings for which, in the opinion of the investigator, participation in the study would not be in the best interest of the participant (e.g., could compromise participant's wellbeing) or that could prevent, limit, or confound the protocol-specified assessments. 5. individuals with medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. 6. history of cancer requiring chemotherapy or radiation within 5 years. 7. lack of participant's capacity (mental, social, behavioral), in the investigator's judgement, to provide informed consent for participation in the study. 8. known or suspected impairment of immunological function, including but not limited to: 1. autoimmune diseases (e.g., multiple sclerosis, type 1 diabetes, myasthenia gravis, crohn's disease and other inflammatory bowel diseases, celiac disease, systemic lupus erythematosus, scleroderma, including diffuse systemic form and crest syndrome, systemic sclerosis, dermatomyositis polymyositis, rheumatoid arthritis, juvenile idiopathic arthritis, autoimmune thyroiditis - including hashimoto thyroiditis, grave's or basedow's disease, immune thrombocytopenic purpura, autoimmune hemolytic anemia, autoimmune hepatitis, psoriasis, vitiligo, vasculitis, guillain- barré syndrome, transverse myelitis, addison's disease, bell's palsy and alopecia areata) or abnormal or positive test result for any of the following tests at the study screening visit: * ana (antinuclear antibody) * rf (rheumatoid factor) * ttg-iga (tissue transglutaminase iga antibody) * crp (c-reactive protein) * tgab (thyroglobulin antibody) 2. primary immunodeficiency disorders (e.g., common variable immune deficiency (cvid), defective phagocytic cell function and neutropenia syndromes, complement deficiency). 3. secondary immunodeficiency disorders (e.g., acquired immunodeficiency syndrome caused by human immunodeficiency virus infection (hiv/aids), solid organ transplant, splenectomy) 9. history of allergic reactions or anaphylactic reaction to any vaccine component. 10. known infection with human immunodeficiency virus (hiv), hepatitis c virus (hcv), or hepatitis b virus (hbv). negative result of anti-hiv, anti-hcv and hbsag testing at screening is required for eligibility. 11. pregnant or breastfeeding or plans to conceive from 2 weeks before the study until the end of study. 12. clinically significant abnormal physical examination, vital signs, or clinically significant abnormal values for hematology, serum chemistry or urinalysis at screening as determined by the investigator. 13. any laboratory test abnormality that would be considered of grade 1 severity or above (as per fda grading guidelines) and is considered as clinically significant by the investigator. grade 2 severity or above is exclusionary, regardless of clinical assessment. 14. receipt of blood products or immunoglobulin within 90 days prior to enrollment or likely to require blood products during the study period. 15. chronic administration (defined as more than 14 days in total) of immune-suppressive or other immune-modifying drug within 6 months prior to enrollment (for corticosteroids, this is defined as prednisone ≥20 mg/day or equivalent). inhaled and topical steroids are allowed. 16. immunization with attenuated vaccines (e.g., shingles) within 4 weeks prior to enrollment. 17. immunization with inactivated vaccines (e.g., influenza) within 2 weeks prior to enrollment. 18. participation in another clinical study within 30 days prior to enrollment. participants who received one or more doses of vbi-2902a or vbi-2905a or other investigational covid-19 vaccines are not eligible for the study. 19. any skin abnormality or tattoo that would limit post-vaccination injection site assessment. 20. family members of study site personnel.

1. history of covid-19 illness of moderate or greater severity, defined as one of the following: 1. moderate illness: individuals who show evidence of lower respiratory disease during clinical assessment or imaging and who have an oxygen saturation (spo2) ≥94% on room air at sea level. 2. severe covid-19 illness: individuals who have spo2 \<94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) \<300 mm hg, a respiratory rate \>30 breaths/min, or lung infiltrates \>50%. 3. critical covid-19 illness: individuals who have respiratory failure, septic shock, and/or multiple organ dysfunction. 2. positive sars-cov-2 pcr or rapid antigen test at screening. 3. history of sars or mers. 4. participant with a history of an underlying clinically significant acute or chronic medical condition or physical examination findings for which, in the opinion of the investigator, participation in the study would not be in the best interest of the participant (e.g., could compromise participant's wellbeing) or that could prevent, limit, or confound the protocol-specified assessments. 5. individuals with medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. 6. history of cancer requiring chemotherapy or radiation within 5 years. 7. lack of participant's capacity (mental, social, behavioral), in the investigator's judgement, to provide informed consent for participation in the study. 8. known or suspected impairment of immunological function, including but not limited to: 1. autoimmune diseases (e.g., multiple sclerosis, type 1 diabetes, myasthenia gravis, crohn's disease and other inflammatory bowel diseases, celiac disease, systemic lupus erythematosus, scleroderma, including diffuse systemic form and crest syndrome, systemic sclerosis, dermatomyositis polymyositis, rheumatoid arthritis, juvenile idiopathic arthritis, autoimmune thyroiditis - including hashimoto thyroiditis, grave's or basedow's disease, immune thrombocytopenic purpura, autoimmune hemolytic anemia, autoimmune hepatitis, psoriasis, vitiligo, vasculitis, guillain- barré syndrome, transverse myelitis, addison's disease, bell's palsy and alopecia areata) or abnormal or positive test result for any of the following tests at the study screening visit: * ana (antinuclear antibody) * rf (rheumatoid factor) * ttg-iga (tissue transglutaminase iga antibody) * crp (c-reactive protein) * tgab (thyroglobulin antibody) 2. primary immunodeficiency disorders (e.g., common variable immune deficiency (cvid), defective phagocytic cell function and neutropenia syndromes, complement deficiency). 3. secondary immunodeficiency disorders (e.g., acquired immunodeficiency syndrome caused by human immunodeficiency virus infection (hiv/aids), solid organ transplant, splenectomy) 9. history of allergic reactions or anaphylactic reaction to any vaccine component. 10. known infection with human immunodeficiency virus (hiv), hepatitis c virus (hcv), or hepatitis b virus (hbv). negative result of anti-hiv, anti-hcv and hbsag testing at screening is required for eligibility. 11. pregnant or breastfeeding or plans to conceive from 2 weeks before the study until the end of study. 12. clinically significant abnormal physical examination, vital signs, or clinically significant abnormal values for hematology, serum chemistry or urinalysis at screening as determined by the investigator. 13. any laboratory test abnormality that would be considered of grade 1 severity or above (as per fda grading guidelines) and is considered as clinically significant by the investigator. grade 2 severity or above is exclusionary, regardless of clinical assessment. 14. receipt of blood products or immunoglobulin within 90 days prior to enrollment or likely to require blood products during the study period. 15. chronic administration (defined as more than 14 days in total) of immune-suppressive or other immune-modifying drug within 6 months prior to enrollment (for corticosteroids, this is defined as prednisone ≥20 mg/day or equivalent). inhaled and topical steroids are allowed. 16. immunization with attenuated vaccines (e.g., shingles) within 4 weeks prior to enrollment. 17. immunization with inactivated vaccines (e.g., influenza) within 2 weeks prior to enrollment. 18. participation in another clinical study within 30 days prior to enrollment. participants who received one or more doses of vbi-2902a or vbi-2905a or other investigational covid-19 vaccines are not eligible for the study. 19. any skin abnormality or tattoo that would limit post-vaccination injection site assessment. 20. family members of study site personnel.

history of covid-19 illness of moderate or greater severity, defined as one of the following: moderate illness: individuals who show evidence of lower respiratory disease during clinical assessment or imaging and who have an oxygen saturation (spo2) ≥94% on room air at sea level. severe covid-19 illness: individuals who have spo2 <94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) <300 mm hg, a respiratory rate >30 breaths/min, or lung infiltrates >50%. critical covid-19 illness: individuals who have respiratory failure, septic shock, and/or multiple organ dysfunction. positive sars-cov-2 pcr or rapid antigen test at screening. history of sars or mers. participant with a history of an underlying clinically significant acute or chronic medical condition or physical examination findings for which, in the opinion of the investigator, participation in the study would not be in the best interest of the participant (e.g., could compromise participant's wellbeing) or that could prevent, limit, or confound the protocol-specified assessments. individuals with medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. history of cancer requiring chemotherapy or radiation within 5 years. lack of participant's capacity (mental, social, behavioral), in the investigator's judgement, to provide informed consent for participation in the study. known or suspected impairment of immunological function, including but not limited to: autoimmune diseases (e.g., multiple sclerosis, type 1 diabetes, myasthenia gravis, crohn's disease and other inflammatory bowel diseases, celiac disease, systemic lupus erythematosus, scleroderma, including diffuse systemic form and crest syndrome, systemic sclerosis, dermatomyositis polymyositis, rheumatoid arthritis, juvenile idiopathic arthritis, autoimmune thyroiditis - including hashimoto thyroiditis, grave's or basedow's disease, immune thrombocytopenic purpura, autoimmune hemolytic anemia, autoimmune hepatitis, psoriasis, vitiligo, vasculitis, guillain- barré syndrome, transverse myelitis, addison's disease, bell's palsy and alopecia areata) or abnormal or positive test result for any of the following tests at the study screening visit: ana (antinuclear antibody) rf (rheumatoid factor) ttg-iga (tissue transglutaminase iga antibody) crp (c-reactive protein) tgab (thyroglobulin antibody) primary immunodeficiency disorders (e.g., common variable immune deficiency (cvid), defective phagocytic cell function and neutropenia syndromes, complement deficiency). secondary immunodeficiency disorders (e.g., acquired immunodeficiency syndrome caused by human immunodeficiency virus infection (hiv/aids), solid organ transplant, splenectomy) history of allergic reactions or anaphylactic reaction to any vaccine component. known infection with human immunodeficiency virus (hiv), hepatitis c virus (hcv), or hepatitis b virus (hbv). negative result of anti-hiv, anti-hcv and hbsag testing at screening is required for eligibility. pregnant or breastfeeding or plans to conceive from 2 weeks before the study until the end of study. clinically significant abnormal physical examination, vital signs, or clinically significant abnormal values for hematology, serum chemistry or urinalysis at screening as determined by the investigator. any laboratory test abnormality that would be considered of grade 1 severity or above (as per fda grading guidelines) and is considered as clinically significant by the investigator. grade 2 severity or above is exclusionary, regardless of clinical assessment. receipt of blood products or immunoglobulin within 90 days prior to enrollment or likely to require blood products during the study period. chronic administration (defined as more than 14 days in total) of immune-suppressive or other immune-modifying drug within 6 months prior to enrollment (for corticosteroids, this is defined as prednisone ≥20 mg/day or equivalent). inhaled and topical steroids are allowed. immunization with attenuated vaccines (e.g., shingles) within 4 weeks prior to enrollment. immunization with inactivated vaccines (e.g., influenza) within 2 weeks prior to enrollment. participation in another clinical study within 30 days prior to enrollment. participants who received one or more doses of vbi-2902a or vbi-2905a or other investigational covid-19 vaccines are not eligible for the study. any skin abnormality or tattoo that would limit post-vaccination injection site assessment. family members of study site personnel.

history of covid-19 illness of moderate or greater severity, defined as one of the following: moderate illness: individuals who show evidence of lower respiratory disease during clinical assessment or imaging and who have an oxygen saturation (spo2) ≥94% on room air at sea level. severe covid-19 illness: individuals who have spo2 <94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (pao2/fio2) <300 mm hg, a respiratory rate >30 breaths/min, or lung infiltrates >50%. critical covid-19 illness: individuals who have respiratory failure, septic shock, and/or multiple organ dysfunction. positive sars-cov-2 pcr or rapid antigen test at screening. history of sars or mers. participant with a history of an underlying clinically significant acute or chronic medical condition or physical examination findings for which, in the opinion of the investigator, participation in the study would not be in the best interest of the participant (e.g., could compromise participant's wellbeing) or that could prevent, limit, or confound the protocol-specified assessments. individuals with medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. history of cancer requiring chemotherapy or radiation within 5 years. lack of participant's capacity (mental, social, behavioral), in the investigator's judgement, to provide informed consent for participation in the study. known or suspected impairment of immunological function, including but not limited to: autoimmune diseases (e.g., multiple sclerosis, type 1 diabetes, myasthenia gravis, crohn's disease and other inflammatory bowel diseases, celiac disease, systemic lupus erythematosus, scleroderma, including diffuse systemic form and crest syndrome, systemic sclerosis, dermatomyositis polymyositis, rheumatoid arthritis, juvenile idiopathic arthritis, autoimmune thyroiditis - including hashimoto thyroiditis, grave's or basedow's disease, immune thrombocytopenic purpura, autoimmune hemolytic anemia, autoimmune hepatitis, psoriasis, vitiligo, vasculitis, guillain- barré syndrome, transverse myelitis, addison's disease, bell's palsy and alopecia areata) or abnormal or positive test result for any of the following tests at the study screening visit: ana (antinuclear antibody) rf (rheumatoid factor) ttg-iga (tissue transglutaminase iga antibody) crp (c-reactive protein) tgab (thyroglobulin antibody) primary immunodeficiency disorders (e.g., common variable immune deficiency (cvid), defective phagocytic cell function and neutropenia syndromes, complement deficiency). secondary immunodeficiency disorders (e.g., acquired immunodeficiency syndrome caused by human immunodeficiency virus infection (hiv/aids), solid organ transplant, splenectomy) history of allergic reactions or anaphylactic reaction to any vaccine component. known infection with human immunodeficiency virus (hiv), hepatitis c virus (hcv), or hepatitis b virus (hbv). negative result of anti-hiv, anti-hcv and hbsag testing at screening is required for eligibility. pregnant or breastfeeding or plans to conceive from 2 weeks before the study until the end of study. clinically significant abnormal physical examination, vital signs, or clinically significant abnormal values for hematology, serum chemistry or urinalysis at screening as determined by the investigator. any laboratory test abnormality that would be considered of grade 1 severity or above (as per fda grading guidelines) and is considered as clinically significant by the investigator. grade 2 severity or above is exclusionary, regardless of clinical assessment. receipt of blood products or immunoglobulin within 90 days prior to enrollment or likely to require blood products during the study period. chronic administration (defined as more than 14 days in total) of immune-suppressive or other immune-modifying drug within 6 months prior to enrollment (for corticosteroids, this is defined as prednisone ≥20 mg/day or equivalent). inhaled and topical steroids are allowed. immunization with attenuated vaccines (e.g., shingles) within 4 weeks prior to enrollment. immunization with inactivated vaccines (e.g., influenza) within 2 weeks prior to enrollment. participation in another clinical study within 30 days prior to enrollment. participants who received one or more doses of vbi-2902a or vbi-2905a or other investigational covid-19 vaccines are not eligible for the study. any skin abnormality or tattoo that would limit post-vaccination injection site assessment. family members of study site personnel.