1. known history of confirmed covid-19 infection 2. known active sepsis or active malignancy 3. known increased infection risk due to underlying immunosuppressed state which includes: * prior organ or hematopoietic stem cell transplant * neutropenia with absolute neutrophil count (anc) \<500 cells/ul at the time of study inclusion * known hiv infection with cd4 \<200 cells/ul at the time of study inclusion * on concomitant immunosuppressants or corticosteroid at a dose of prednisolone equivalent dose 10mg or more for more than 3 months 4. known history or active infective endocarditis 5. on peritoneal dialysis or haemodialysis 6. documented pregnancy substudy 2 inclusion criteria: 1. age 65 years and above 2. written informed consents obtained

1. known history of confirmed covid-19 infection 2. known active sepsis or active malignancy 3. known increased infection risk due to underlying immunosuppressed state which includes: * prior organ or hematopoietic stem cell transplant * neutropenia with absolute neutrophil count (anc) \<500 cells/ul at the time of study inclusion * known hiv infection with cd4 \<200 cells/ul at the time of study inclusion * on concomitant immunosuppressants or corticosteroid at a dose of prednisolone equivalent dose 10mg or more for more than 3 months 4. known history or active infective endocarditis 5. on peritoneal dialysis or haemodialysis 6. documented pregnancy substudy 2 inclusion criteria: 1. age 65 years and above 2. written informed consents obtained

known history of confirmed covid-19 infection known active sepsis or active malignancy known increased infection risk due to underlying immunosuppressed state which includes: prior organ or hematopoietic stem cell transplant neutropenia with absolute neutrophil count (anc) <500 cells/ul at the time of study inclusion known hiv infection with cd4 <200 cells/ul at the time of study inclusion on concomitant immunosuppressants or corticosteroid at a dose of prednisolone equivalent dose 10mg or more for more than 3 months known history or active infective endocarditis on peritoneal dialysis or haemodialysis documented pregnancy substudy 2 inclusion criteria: age 65 years and above written informed consents obtained

known history of confirmed covid-19 infection known active sepsis or active malignancy known increased infection risk due to underlying immunosuppressed state which includes: prior organ or hematopoietic stem cell transplant neutropenia with absolute neutrophil count (anc) <500 cells/ul at the time of study inclusion known hiv infection with cd4 <200 cells/ul at the time of study inclusion on concomitant immunosuppressants or corticosteroid at a dose of prednisolone equivalent dose 10mg or more for more than 3 months known history or active infective endocarditis on peritoneal dialysis or haemodialysis documented pregnancy substudy 2 inclusion criteria: age 65 years and above written informed consents obtained

1. known history of confirmed covid-19 infection 2. known active sepsis or active malignancy 3. known increased infection risk due to underlying immunosuppressed state which includes: - prior organ or hematopoietic stem cell transplant - neutropenia with absolute neutrophil count (anc) <500 cells/ul at the time of study inclusion - known hiv infection with cd4 <200 cells/ul at the time of study inclusion - on concomitant immunosuppressants or corticosteroid at a dose of prednisolone equivalent dose 10mg or more for more than 3 months 4. known history or active infective endocarditis 5. on peritoneal dialysis or haemodialysis 6. documented pregnancy substudy 2 inclusion criteria: 1. age 65 years and above 2. written informed consents obtained

1. known history of confirmed covid-19 infection 2. known active sepsis or active malignancy 3. known increased infection risk due to underlying immunosuppressed state which includes: - prior organ or hematopoietic stem cell transplant - neutropenia with absolute neutrophil count (anc) <500 cells/ul at the time of study inclusion - known hiv infection with cd4 <200 cells/ul at the time of study inclusion - on concomitant immunosuppressants or corticosteroid at a dose of prednisolone equivalent dose 10mg or more for more than 3 months 4. known history or active infective endocarditis 5. on peritoneal dialysis or haemodialysis 6. documented pregnancy substudy 2 inclusion criteria: 1. age 65 years and above 2. written informed consents obtained