1. known history of covid-19 infection. 2. for women of child bearing potential, a positive serum pregnancy test (during screening within 45 days of enrolment) or positive urine pregnancy test (within 24 hours of administering of vaccine). 3. temperature \>38.0°c (100.4°f) or symptoms of an acute self limiting illness such as an upper respiratory infection or gastroenteritis within three days prior to vaccination. 4. medical problems because of alcohol or illicit drug use during the past 12 months. 5. receipt of an experimental agent (vaccine, drug, device, etc.) within 60 days before enrolment or expects to receive an investigational agent during the study period. 6. receipt of any licensed vaccine within four weeks before enrolment in this study. 7. known sensitivity to any ingredient of the study vaccines, or a more severe allergic reaction and history of allergies in the past. 8. receipt of immunoglobulin or other blood products within the three months prior to vaccination in this study. 9. immunosuppression because of an underlying illness or treatment with immunosuppressive or cytotoxic drugs or use of anticancer chemotherapy or radiation therapy within the preceding 36 months. 10. long-term use (\> 2 weeks) of oral or parenteral steroids (glucocorticoids) or high dose inhaled steroids (\>800 mcg/day of beclomethasone dipropionate or equivalent) within the preceding six months (nasal and topical steroids are allowed). 11. any history of anaphylaxis in relation to vaccination. 12. history of any cancer. 13. history of severe psychiatric conditions likely to affect participation in the study. 14. a bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder, or prior history of significant bleeding or bruising following im injections or venepuncture). 15. any other serious chronic illness requiring immediate hospital specialist supervision. 16. any other condition that in the opinion of the investigator would jeopardize the safety or rights of a volunteer participating in the trial or would render the subject unable to comply with the protocol.

1. known history of covid-19 infection. 2. for women of child bearing potential, a positive serum pregnancy test (during screening within 45 days of enrolment) or positive urine pregnancy test (within 24 hours of administering of vaccine). 3. temperature \>38.0°c (100.4°f) or symptoms of an acute self limiting illness such as an upper respiratory infection or gastroenteritis within three days prior to vaccination. 4. medical problems because of alcohol or illicit drug use during the past 12 months. 5. receipt of an experimental agent (vaccine, drug, device, etc.) within 60 days before enrolment or expects to receive an investigational agent during the study period. 6. receipt of any licensed vaccine within four weeks before enrolment in this study. 7. known sensitivity to any ingredient of the study vaccines, or a more severe allergic reaction and history of allergies in the past. 8. receipt of immunoglobulin or other blood products within the three months prior to vaccination in this study. 9. immunosuppression because of an underlying illness or treatment with immunosuppressive or cytotoxic drugs or use of anticancer chemotherapy or radiation therapy within the preceding 36 months. 10. long-term use (\> 2 weeks) of oral or parenteral steroids (glucocorticoids) or high dose inhaled steroids (\>800 mcg/day of beclomethasone dipropionate or equivalent) within the preceding six months (nasal and topical steroids are allowed). 11. any history of anaphylaxis in relation to vaccination. 12. history of any cancer. 13. history of severe psychiatric conditions likely to affect participation in the study. 14. a bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder, or prior history of significant bleeding or bruising following im injections or venepuncture). 15. any other serious chronic illness requiring immediate hospital specialist supervision. 16. any other condition that in the opinion of the investigator would jeopardize the safety or rights of a volunteer participating in the trial or would render the subject unable to comply with the protocol.

known history of covid-19 infection. for women of child bearing potential, a positive serum pregnancy test (during screening within 45 days of enrolment) or positive urine pregnancy test (within 24 hours of administering of vaccine). temperature >38.0°c (100.4°f) or symptoms of an acute self limiting illness such as an upper respiratory infection or gastroenteritis within three days prior to vaccination. medical problems because of alcohol or illicit drug use during the past 12 months. receipt of an experimental agent (vaccine, drug, device, etc.) within 60 days before enrolment or expects to receive an investigational agent during the study period. receipt of any licensed vaccine within four weeks before enrolment in this study. known sensitivity to any ingredient of the study vaccines, or a more severe allergic reaction and history of allergies in the past. receipt of immunoglobulin or other blood products within the three months prior to vaccination in this study. immunosuppression because of an underlying illness or treatment with immunosuppressive or cytotoxic drugs or use of anticancer chemotherapy or radiation therapy within the preceding 36 months. long-term use (> 2 weeks) of oral or parenteral steroids (glucocorticoids) or high dose inhaled steroids (>800 mcg/day of beclomethasone dipropionate or equivalent) within the preceding six months (nasal and topical steroids are allowed). any history of anaphylaxis in relation to vaccination. history of any cancer. history of severe psychiatric conditions likely to affect participation in the study. a bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder, or prior history of significant bleeding or bruising following im injections or venepuncture). any other serious chronic illness requiring immediate hospital specialist supervision. any other condition that in the opinion of the investigator would jeopardize the safety or rights of a volunteer participating in the trial or would render the subject unable to comply with the protocol.

known history of covid-19 infection. for women of child bearing potential, a positive serum pregnancy test (during screening within 45 days of enrolment) or positive urine pregnancy test (within 24 hours of administering of vaccine). temperature >38.0°c (100.4°f) or symptoms of an acute self limiting illness such as an upper respiratory infection or gastroenteritis within three days prior to vaccination. medical problems because of alcohol or illicit drug use during the past 12 months. receipt of an experimental agent (vaccine, drug, device, etc.) within 60 days before enrolment or expects to receive an investigational agent during the study period. receipt of any licensed vaccine within four weeks before enrolment in this study. known sensitivity to any ingredient of the study vaccines, or a more severe allergic reaction and history of allergies in the past. receipt of immunoglobulin or other blood products within the three months prior to vaccination in this study. immunosuppression because of an underlying illness or treatment with immunosuppressive or cytotoxic drugs or use of anticancer chemotherapy or radiation therapy within the preceding 36 months. long-term use (> 2 weeks) of oral or parenteral steroids (glucocorticoids) or high dose inhaled steroids (>800 mcg/day of beclomethasone dipropionate or equivalent) within the preceding six months (nasal and topical steroids are allowed). any history of anaphylaxis in relation to vaccination. history of any cancer. history of severe psychiatric conditions likely to affect participation in the study. a bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder, or prior history of significant bleeding or bruising following im injections or venepuncture). any other serious chronic illness requiring immediate hospital specialist supervision. any other condition that in the opinion of the investigator would jeopardize the safety or rights of a volunteer participating in the trial or would render the subject unable to comply with the protocol.