1. Participation in COVID-19 prophylactic drug trials for the duration of the study. 2. Future participation in SARS-CoV-2 serological surveys where participants are informed of their serostatus for the duration of the study. 3. Participation in research involving an investigational product (drug/biologic/device) within 45 days prior to first study vaccination. 4. History of laboratory-confirmed (by PCR or serology to SARS-CoV-2) COVID-19 infection at any time prior to randomisation. 5. Administration of immunoglobulins and/or any blood products within the 3 months preceding the planned administration of the study vaccine candidate. 6. Any confirmed or suspected immunosuppressive or immunodeficient state, chronic administration (defined as more than 14 continuous days) of immunosuppressant medication within the past 3 months, except topical steroids or short-term oral steroids (course lasting ≤ 14 days). NOTE: An immunosuppressant dose of glucocorticoid is defined as a systemic dose ≥ 10 mg of prednisone per day or equivalent. The use of topical, inhaled, and nasal glucocorticoids will be permitted if other chronic disease conditions are not exclusionary. HIV-positive participants receiving highly active antiretroviral therapy and a history within 6 months of screening of viral load < 1000 copies/mL or CD4 count > 300 cells/mm3 would be eligible. 7. History of allergic disease or reactions likely to be exacerbated by any component of the study vaccines. 8. Any history of anaphylaxis to any prior vaccine. 9. Pregnancy, lactation or willingness/intention to become pregnant within 3 months following the last study vaccination. 10. Current diagnosis of or treatment for cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ, at the discretion of the investigator). 11. Bleeding disorder (e.g., factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following IM injections or venepuncture. 12. Continuous use of anticoagulants, such as coumarins and related anticoagulants (i.e., warfarin) or novel oral anticoagulants/anti-platelet agents. (NOTE: The use of ≤ 325 mg of aspirin per day as prophylaxis is permitted) 13. Suspected or known current alcohol or drug dependency. 14. Study team member or first-degree relative of any study team member (inclusive of sponsor, contract research organisation (CRO), and site personnel involved in the study). 15. Participants who are having any current workup of undiagnosed illness within the last 8 weeks that is either participant-reported or has been clinician-assessed, which could lead to a new condition or diagnosis. 16. Received any live vaccine within 4 weeks or any vaccine (excluding influenza) within 2 weeks prior to first study vaccination or any licensed influenza vaccine within 1 week prior to first study vaccination or plans to receive any vaccine from these time periods until 28 days after second study vaccination. NOTE: In addition, a licensed seasonal influenza vaccine may be given 7 days after dose 1 and dose 2 but should not be given within 7 days of dose 2. 17. Have clinically significant chronic cardiovascular, endocrine, gastrointestinal, hepatic (including hepatitis B and C), renal, neurological, respiratory, psychiatric or other medical disorders not excluded by other exclusion criteria, that are assessed by the investigator as being clinically unstable within the prior 4 weeks as evidenced by: a. Hospitalisation for the condition, including day surgical interventions. b. New significant organ function deterioration. c. Needing addition of new treatments or major dose adjustments of current treatments (mild or moderate well-controlled comorbidities are allowed). 18. History of chronic neurological disorders that have required prior specialist physician review for diagnosis and management (multiple sclerosis, dementia, transient ischemic attacks, Parkinson's disease, degenerative neurological conditions and neuropathy) or a history of stroke or previous neurological disorder within 12 months with residual symptoms. Participants with a history of migraine or chronic headaches or nerve root compression that have been stable on treatment for the last 4 weeks are not excluded. 19. Any autoimmune disease/condition (iatrogenic or congenital) in Table 9-3 or being treated with a biologic therapy. 20. Any other significant disease, disorder or finding that, in the opinion of the investigator, may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study, or impair interpretation of the study data. 21. Participant requires the use of continuous oxygen therapy or any oxygen therapy while awake or is anticipated to require daytime oxygen therapy during the course of the study. NOTE: Nocturnal oxygen use only is acceptable for study inclusion.

1. Participation in COVID-19 prophylactic drug trials for the duration of the study. 2. Future participation in SARS-CoV-2 serological surveys where participants are informed of their serostatus for the duration of the study. 3. Participation in research involving an investigational product (drug/biologic/device) within 45 days prior to first study vaccination. 4. History of laboratory-confirmed (by PCR or serology to SARS-CoV-2) COVID-19 infection at any time prior to randomisation. 5. Administration of immunoglobulins and/or any blood products within the 3 months preceding the planned administration of the study vaccine candidate. 6. Any confirmed or suspected immunosuppressive or immunodeficient state, chronic administration (defined as more than 14 continuous days) of immunosuppressant medication within the past 3 months, except topical steroids or short-term oral steroids (course lasting ≤ 14 days). NOTE: An immunosuppressant dose of glucocorticoid is defined as a systemic dose ≥ 10 mg of prednisone per day or equivalent. The use of topical, inhaled, and nasal glucocorticoids will be permitted if other chronic disease conditions are not exclusionary. HIV-positive participants receiving highly active antiretroviral therapy and a history within 6 months of screening of viral load < 1000 copies/mL or CD4 count > 300 cells/mm3 would be eligible. 7. History of allergic disease or reactions likely to be exacerbated by any component of the study vaccines. 8. Any history of anaphylaxis to any prior vaccine. 9. Pregnancy, lactation or willingness/intention to become pregnant within 3 months following the last study vaccination. 10. Current diagnosis of or treatment for cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ, at the discretion of the investigator). 11. Bleeding disorder (e.g., factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following IM injections or venepuncture. 12. Continuous use of anticoagulants, such as coumarins and related anticoagulants (i.e., warfarin) or novel oral anticoagulants/anti-platelet agents. (NOTE: The use of ≤ 325 mg of aspirin per day as prophylaxis is permitted) 13. Suspected or known current alcohol or drug dependency. 14. Study team member or first-degree relative of any study team member (inclusive of sponsor, contract research organisation (CRO), and site personnel involved in the study). 15. Participants who are having any current workup of undiagnosed illness within the last 8 weeks that is either participant-reported or has been clinician-assessed, which could lead to a new condition or diagnosis. 16. Received any live vaccine within 4 weeks or any vaccine (excluding influenza) within 2 weeks prior to first study vaccination or any licensed influenza vaccine within 1 week prior to first study vaccination or plans to receive any vaccine from these time periods until 28 days after second study vaccination. NOTE: In addition, a licensed seasonal influenza vaccine may be given 7 days after dose 1 and dose 2 but should not be given within 7 days of dose 2. 17. Have clinically significant chronic cardiovascular, endocrine, gastrointestinal, hepatic (including hepatitis B and C), renal, neurological, respiratory, psychiatric or other medical disorders not excluded by other exclusion criteria, that are assessed by the investigator as being clinically unstable within the prior 4 weeks as evidenced by: a. Hospitalisation for the condition, including day surgical interventions. b. New significant organ function deterioration. c. Needing addition of new treatments or major dose adjustments of current treatments (mild or moderate well-controlled comorbidities are allowed). 18. History of chronic neurological disorders that have required prior specialist physician review for diagnosis and management (multiple sclerosis, dementia, transient ischemic attacks, Parkinson's disease, degenerative neurological conditions and neuropathy) or a history of stroke or previous neurological disorder within 12 months with residual symptoms. Participants with a history of migraine or chronic headaches or nerve root compression that have been stable on treatment for the last 4 weeks are not excluded. 19. Any autoimmune disease/condition (iatrogenic or congenital) in Table 9-3 or being treated with a biologic therapy. 20. Any other significant disease, disorder or finding that, in the opinion of the investigator, may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study, or impair interpretation of the study data. 21. Participant requires the use of continuous oxygen therapy or any oxygen therapy while awake or is anticipated to require daytime oxygen therapy during the course of the study. NOTE: Nocturnal oxygen use only is acceptable for study inclusion.

1. Participation in COVID-19 prophylactic drug trials for the duration of the study. 2. Participation in SARS-CoV-2 serological surveys where participants are informed of their serostatus for the duration of the study. 3. Participation in research involving an investigational product (drug/biologic/device) within 45 days prior to first study vaccination. 4. History of laboratory-confirmed (by PCR or serology to SARS-CoV-2) COVID-19 infection at any time prior to randomisation. 5. Administration of immunoglobulins and/or any blood products within the 3 months preceding the planned administration of the study vaccine candidate. 6. Any confirmed or suspected immunosuppressive or immunodeficient state, chronic administration (defined as more than 14 continuous days) of immunosuppressant medication within the past 3 months, except topical steroids or short-term oral steroids (course lasting ≤ 14 days). NOTE: An immunosuppressant dose of glucocorticoid is defined as a systemic dose ≥ 10 mg of prednisone per day or equivalent. The use of topical, inhaled, and nasal glucocorticoids will be permitted if other chronic disease conditions are not exclusionary. 7. History of allergic disease or reactions likely to be exacerbated by any component of the study vaccines. 8. Any history of anaphylaxis to any prior vaccine. 9. Pregnancy, lactation or willingness/intention to become pregnant during the study. 10. Current diagnosis of or treatment for cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ, at the discretion of the investigator). 11. Bleeding disorder (e.g., factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following IM injections or venepuncture. 12. Continuous use of anticoagulants, such as coumarins and related anticoagulants (i.e., warfarin) or novel oral anticoagulants/anti-platelet agents. NOTE: The use of ≤ 325 mg of aspirin per day as prophylaxis is permitted. 13. Suspected or known current alcohol or drug dependency. 14. Study team member or first-degree relative of any study team member (inclusive of sponsor, contract research organisation (CRO), and site personnel involved in the study). 15. Participants who are having any current workup of undiagnosed illness within the last 8 weeks that is either participant-reported or has been clinician-assessed, which could lead to a new condition or diagnosis. 16. Received any live vaccine within 4 weeks or any vaccine (excluding influenza) within 2 weeks prior to first study vaccination or any licensed influenza vaccine within 1 week prior to first study vaccination. Plans to receive any vaccine from these time periods until 28 days after second study vaccination (with the exception of participants in the seasonal influenza co-administration sub-study, a licensed seasonal influenza vaccine may be received as soon as 7 days after second study vaccination). NOTE: An influenza co-administration sub-study will occur in which 400 participants will receive a single dose of seasonal influenza vaccine at the same time as first study vaccination. 17. Have clinically significant chronic cardiovascular, endocrine, gastrointestinal, hepatic, renal, neurological, respiratory, psychiatric or other medical disorders not excluded by other exclusion criteria, that are assessed by the investigator as being clinically unstable within the prior 4 weeks as evidenced by: a. Hospitalisation for the condition, including day surgical interventions. b. New significant organ function deterioration. c. Needing addition of new treatments or major dose adjustments of current treatments (mild or moderate well-controlled comorbidities are allowed). 18. History of chronic neurological disorders that have required prior specialist physician review for diagnosis and management (such as multiple sclerosis, dementia, transient ischemic attacks, Parkinson’s disease, degenerative neurological conditions, neuropathy, and epilepsy) or a history of stroke or previous neurological disorder within 12 months with residual symptoms. Participants with a history of migraine or chronic headaches or nerve root compression that have been stable on treatment for the last 4 weeks are not excluded. 19. Any autoimmune or immunodeficiency disease/condition (iatrogenic or congenital). NOTE: Stable endocrine disorders that have a confirmed autoimmune etiology (e.g., thyroid, pancreatic) are allowed. 20. Any other significant disease, disorder or finding that, in the opinion of the investigator, may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study, or impair interpretation of the study data.

1. Participation in COVID-19 prophylactic drug trials for the duration of the study. 2. Participation in SARS-CoV-2 serological surveys where participants are informed of their serostatus for the duration of the study. 3. Participation in research involving an investigational product (drug/biologic/device) within 45 days prior to first study vaccination. 4. History of laboratory-confirmed (by PCR or serology to SARS-CoV-2) COVID-19 infection at any time prior to randomisation. 5. Administration of immunoglobulins and/or any blood products within the 3 months preceding the planned administration of the study vaccine candidate. 6. Any confirmed or suspected immunosuppressive or immunodeficient state, chronic administration (defined as more than 14 continuous days) of immunosuppressant medication within the past 3 months, except topical steroids or short-term oral steroids (course lasting ≤ 14 days). NOTE: An immunosuppressant dose of glucocorticoid is defined as a systemic dose ≥ 10 mg of prednisone per day or equivalent. The use of topical, inhaled, and nasal glucocorticoids will be permitted if other chronic disease conditions are not exclusionary. 7. History of allergic disease or reactions likely to be exacerbated by any component of the study vaccines. 8. Any history of anaphylaxis to any prior vaccine. 9. Pregnancy, lactation or willingness/intention to become pregnant during the study. 10. Current diagnosis of or treatment for cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ, at the discretion of the investigator). 11. Bleeding disorder (e.g., factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following IM injections or venepuncture. 12. Continuous use of anticoagulants, such as coumarins and related anticoagulants (i.e., warfarin) or novel oral anticoagulants/anti-platelet agents. NOTE: The use of ≤ 325 mg of aspirin per day as prophylaxis is permitted. 13. Suspected or known current alcohol or drug dependency. 14. Study team member or first-degree relative of any study team member (inclusive of sponsor, contract research organisation (CRO), and site personnel involved in the study). 15. Participants who are having any current workup of undiagnosed illness within the last 8 weeks that is either participant-reported or has been clinician-assessed, which could lead to a new condition or diagnosis. 16. Received any live vaccine within 4 weeks or any vaccine (excluding influenza) within 2 weeks prior to first study vaccination or any licensed influenza vaccine within 1 week prior to first study vaccination. Plans to receive any vaccine from these time periods until 28 days after second study vaccination (with the exception of participants in the seasonal influenza co-administration sub-study, a licensed seasonal influenza vaccine may be received as soon as 7 days after second study vaccination). NOTE: An influenza co-administration sub-study will occur in which 400 participants will receive a single dose of seasonal influenza vaccine at the same time as first study vaccination. 17. Have clinically significant chronic cardiovascular, endocrine, gastrointestinal, hepatic, renal, neurological, respiratory, psychiatric or other medical disorders not excluded by other exclusion criteria, that are assessed by the investigator as being clinically unstable within the prior 4 weeks as evidenced by: a. Hospitalisation for the condition, including day surgical interventions. b. New significant organ function deterioration. c. Needing addition of new treatments or major dose adjustments of current treatments (mild or moderate well-controlled comorbidities are allowed). 18. History of chronic neurological disorders that have required prior specialist physician review for diagnosis and management (such as multiple sclerosis, dementia, transient ischemic attacks, Parkinson’s disease, degenerative neurological conditions, neuropathy, and epilepsy) or a history of stroke or previous neurological disorder within 12 months with residual symptoms. Participants with a history of migraine or chronic headaches or nerve root compression that have been stable on treatment for the last 4 weeks are not excluded. 19. Any autoimmune or immunodeficiency disease/condition (iatrogenic or congenital). NOTE: Stable endocrine disorders that have a confirmed autoimmune etiology (e.g., thyroid, pancreatic) are allowed. 20. Any other significant disease, disorder or finding that, in the opinion of the investigator, may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study, or impair interpretation of the study data.