1. multi-organ transplant recipient 2. history of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g. anaphylaxis) to any component of the study intervention(s). 3. previous or active covid-19 disease 4. active malignancy, except non-melanoma skin cancer 5. inherited immune deficiency 6. infection with human immunodeficiency virus (hiv) 7. administration of t cell, b cell, or plasma cell depleting antibodies during the last 6 months 8. any vaccination within a week before enrolment 9. bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. additional exclusion criteria for stratum b: 10. history of recurrent venous thrombosis or venous thrombosis \<2 years before baseline 11. immune-mediated diseases associated with thrombocytopenia such as itp and ahus

1. multi-organ transplant recipient 2. history of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g. anaphylaxis) to any component of the study intervention(s). 3. previous or active covid-19 disease 4. active malignancy, except non-melanoma skin cancer 5. inherited immune deficiency 6. infection with human immunodeficiency virus (hiv) 7. administration of t cell, b cell, or plasma cell depleting antibodies during the last 6 months 8. any vaccination within a week before enrolment 9. bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. additional exclusion criteria for stratum b: 10. history of recurrent venous thrombosis or venous thrombosis \<2 years before baseline 11. immune-mediated diseases associated with thrombocytopenia such as itp and ahus

multi-organ transplant recipient history of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g. anaphylaxis) to any component of the study intervention(s). previous or active covid-19 disease active malignancy, except non-melanoma skin cancer inherited immune deficiency infection with human immunodeficiency virus (hiv) administration of t cell, b cell, or plasma cell depleting antibodies during the last 6 months any vaccination within a week before enrolment bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. additional exclusion criteria for stratum b: history of recurrent venous thrombosis or venous thrombosis <2 years before baseline immune-mediated diseases associated with thrombocytopenia such as itp and ahus

multi-organ transplant recipient history of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g. anaphylaxis) to any component of the study intervention(s). previous or active covid-19 disease active malignancy, except non-melanoma skin cancer inherited immune deficiency infection with human immunodeficiency virus (hiv) administration of t cell, b cell, or plasma cell depleting antibodies during the last 6 months any vaccination within a week before enrolment bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. additional exclusion criteria for stratum b: history of recurrent venous thrombosis or venous thrombosis <2 years before baseline immune-mediated diseases associated with thrombocytopenia such as itp and ahus

multi-organ transplant recipient history of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g. anaphylaxis) to any component of the study intervention(s). previous or active covid-19 disease active malignancy, except non-melanoma skin cancer inherited immune deficiency infection with human immunodeficiency virus (hiv) administration of t cell, b cell, or plasma cell depleting antibodies during the last 6 months any vaccination within a month before enrolment bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection.

multi-organ transplant recipient history of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g. anaphylaxis) to any component of the study intervention(s). previous or active covid-19 disease active malignancy, except non-melanoma skin cancer inherited immune deficiency infection with human immunodeficiency virus (hiv) administration of t cell, b cell, or plasma cell depleting antibodies during the last 6 months any vaccination within a month before enrolment bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection.

1. multi-organ transplant recipient 2. history of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g. anaphylaxis) to any component of the study intervention(s). 3. previous or active covid-19 disease 4. active malignancy, except non-melanoma skin cancer 5. inherited immune deficiency 6. infection with human immunodeficiency virus (hiv) 7. administration of t cell, b cell, or plasma cell depleting antibodies during the last 6 months 8. any vaccination within a month before enrolment 9. bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection.

1. multi-organ transplant recipient 2. history of severe adverse reaction associated with a vaccine and/or severe allergic reaction (e.g. anaphylaxis) to any component of the study intervention(s). 3. previous or active covid-19 disease 4. active malignancy, except non-melanoma skin cancer 5. inherited immune deficiency 6. infection with human immunodeficiency virus (hiv) 7. administration of t cell, b cell, or plasma cell depleting antibodies during the last 6 months 8. any vaccination within a month before enrolment 9. bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection.