* acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection * known allergy or contra-indications for vaccines or any vaccine components * any emergency condition requiring immediate hospitalization for any condition * patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to screening visit (day 0) exclusion criteria for pilot trial: * pregnancy * acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection * known allergy or contra-indications for vaccines or any vaccine components * any emergency condition requiring immediate hospitalization for any condition * patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to randomisation * patients with solid organ transplantation (lung or kidney) with the following conditions: 1. solid organ transplant recipients less than one month post-transplantation 2. solid organ transplant recipients with the use of t-cell/b-cell depleting agents in the last 3 months (i. e induction treatment in standard risk or high-risk immunological situation or rejection treatment). 3. solid organ transplant recipients with the need of pulse corticosteroids (\>100mg prednisone or equivalent) in the last 1 month or who have received atg or rituximab in the last 6 months 4. solid organ transplant recipients with the need of any kind of chemotherapy treatment

* acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection * known allergy or contra-indications for vaccines or any vaccine components * any emergency condition requiring immediate hospitalization for any condition * patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to screening visit (day 0) exclusion criteria for pilot trial: * pregnancy * acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection * known allergy or contra-indications for vaccines or any vaccine components * any emergency condition requiring immediate hospitalization for any condition * patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to randomisation * patients with solid organ transplantation (lung or kidney) with the following conditions: 1. solid organ transplant recipients less than one month post-transplantation 2. solid organ transplant recipients with the use of t-cell/b-cell depleting agents in the last 3 months (i. e induction treatment in standard risk or high-risk immunological situation or rejection treatment). 3. solid organ transplant recipients with the need of pulse corticosteroids (\>100mg prednisone or equivalent) in the last 1 month or who have received atg or rituximab in the last 6 months 4. solid organ transplant recipients with the need of any kind of chemotherapy treatment

acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection known allergy or contra-indications for vaccines or any vaccine components any emergency condition requiring immediate hospitalization for any condition patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to screening visit (day 0) exclusion criteria for pilot trial: pregnancy acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection known allergy or contra-indications for vaccines or any vaccine components any emergency condition requiring immediate hospitalization for any condition patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to randomisation patients with solid organ transplantation (lung or kidney) with the following conditions: solid organ transplant recipients less than one month post-transplantation solid organ transplant recipients with the use of t-cell/b-cell depleting agents in the last 3 months (i. e induction treatment in standard risk or high-risk immunological situation or rejection treatment). solid organ transplant recipients with the need of pulse corticosteroids (>100mg prednisone or equivalent) in the last 1 month or who have received atg or rituximab in the last 6 months solid organ transplant recipients with the need of any kind of chemotherapy treatment

acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection known allergy or contra-indications for vaccines or any vaccine components any emergency condition requiring immediate hospitalization for any condition patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to screening visit (day 0) exclusion criteria for pilot trial: pregnancy acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection known allergy or contra-indications for vaccines or any vaccine components any emergency condition requiring immediate hospitalization for any condition patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to randomisation patients with solid organ transplantation (lung or kidney) with the following conditions: solid organ transplant recipients less than one month post-transplantation solid organ transplant recipients with the use of t-cell/b-cell depleting agents in the last 3 months (i. e induction treatment in standard risk or high-risk immunological situation or rejection treatment). solid organ transplant recipients with the need of pulse corticosteroids (>100mg prednisone or equivalent) in the last 1 month or who have received atg or rituximab in the last 6 months solid organ transplant recipients with the need of any kind of chemotherapy treatment

- acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection - known allergy or contra-indications for vaccines or any vaccine components - any emergency condition requiring immediate hospitalization for any condition - patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to screening visit (day 0) exclusion criteria for pilot trial: - pregnancy - acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection - known allergy or contra-indications for vaccines or any vaccine components - any emergency condition requiring immediate hospitalization for any condition - patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to randomisation - patients with solid organ transplantation (lung or kidney) with the following conditions: 1. solid organ transplant recipients less than one month post-transplantation 2. solid organ transplant recipients with the use of t-cell/b-cell depleting agents in the last 3 months (i. e induction treatment in standard risk or high-risk immunological situation or rejection treatment). 3. solid organ transplant recipients with the need of pulse corticosteroids (>100mg prednisone or equivalent) in the last 1 month or who have received atg or rituximab in the last 6 months 4. solid organ transplant recipients with the need of any kind of chemotherapy treatment

- acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection - known allergy or contra-indications for vaccines or any vaccine components - any emergency condition requiring immediate hospitalization for any condition - patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to screening visit (day 0) exclusion criteria for pilot trial: - pregnancy - acute symptomatic sars-cov-2 infection, influenza or other acute respiratory tract infection - known allergy or contra-indications for vaccines or any vaccine components - any emergency condition requiring immediate hospitalization for any condition - patients with previous pcr documented sars-cov-2 infection and, or documented antibodies less than 3 months prior to randomisation - patients with solid organ transplantation (lung or kidney) with the following conditions: 1. solid organ transplant recipients less than one month post-transplantation 2. solid organ transplant recipients with the use of t-cell/b-cell depleting agents in the last 3 months (i. e induction treatment in standard risk or high-risk immunological situation or rejection treatment). 3. solid organ transplant recipients with the need of pulse corticosteroids (>100mg prednisone or equivalent) in the last 1 month or who have received atg or rituximab in the last 6 months 4. solid organ transplant recipients with the need of any kind of chemotherapy treatment