* arm 1 1. previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) 2. have been exposed to a known covid-19 case within the last 72 hours, defined by the current department of health and human services such as household contact, 15 minutes of face to face exposure, 2 hours in close space. 3. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx 4. pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study 5. participant unable to return for regular follow-up 6. life expectancy of less than 4 months 7. participant already included in another intervention study on the prevention of covid-19 8. currently unwell with influenza-like symptoms - if participant is found to be covid-19 negative and becomes asymptomatic, they can be reconsidered for participation arm 2 1. previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) 2. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx 3. pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study 4. patient unable to return for follow-up 5. life expectancy of less than 1 month 6. patient already included in another intervention study on the prevention of covid-19 7. currently unwell with influenza-like symptoms arm 3 1. unable to take oral medication 2. any known allergic reactions to selinexor or concomitant medication-related contra-indications to selinexor. 3. severe critical covid-19 infection defined as: 1. requiring invasive or non-invasive mechanical ventilation, ecmo 2. anticipated unlikely to survive within 48 hours 4. in the opinion of the investigator and primary oncologist, participation in the study would not be in the best interests of the participant 5. severe renal impairment defined as creatinine clearance (crcl) \< 20ml/min as calculated using the cockcroft gault formula 6. severe hepatic impairment defined as aspartate transaminase (ast) or alanine transaminase (alt) \> 5 x upper limit of normal (uln) arm 4 1. invasive mechanical ventilation or extracorporeal membrane oxygenation (ecmo) 2. history of pulmonary alveolar proteinosis (pap). 3. women of childbearing potential who are pregnant or breastfeeding. 4. known hypersensitivity to lenzilumab or any of its components. 5 .use of any fda-approved anti-il-6 therapy (eg. tocilizumab, sarilumab, siltukimab), anti-il-1 therapy (eg. anakinra, canakinumab) or kinase inhibitor (eg.baracitinib, ibrutinib, acalabrutinib) therapy to treat covid-19 within 8 weeks prior to randomization. any live vaccine within 8 weeks prior to randomisation. note that subjects receiving other fda-approved immunomodulators to treat underlying autoimmune disorders such as rheumatoid arthritis, psoriasis, ankylosing spondylitis, asthma, chronic obstructive pulmonary disease, atopic dermatitis, multiple sclerosis, etc. would not be excluded. participants on corticosteroids or dexamethasone are not excluded from the study. note: participants on convalescent plasma, remdesivir and/or hydroxychloroquine with or without azithromycin are not excluded from the study. 6. use of gm-csf agents (e.g., sargramostim) within 8 weeks prior to randomisation. 7. expected survival \< 24h in the opinion of the investigator. 8. any condition that, in the opinion of the investigator, is likely to interfere with the safety and efficacy of the study treatment or puts the subject at unacceptably high risk from the study. 9. participation in another interventional study of covid-19

* arm 1 1. previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) 2. have been exposed to a known covid-19 case within the last 72 hours, defined by the current department of health and human services such as household contact, 15 minutes of face to face exposure, 2 hours in close space. 3. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx 4. pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study 5. participant unable to return for regular follow-up 6. life expectancy of less than 4 months 7. participant already included in another intervention study on the prevention of covid-19 8. currently unwell with influenza-like symptoms - if participant is found to be covid-19 negative and becomes asymptomatic, they can be reconsidered for participation arm 2 1. previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) 2. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx 3. pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study 4. patient unable to return for follow-up 5. life expectancy of less than 1 month 6. patient already included in another intervention study on the prevention of covid-19 7. currently unwell with influenza-like symptoms arm 3 1. unable to take oral medication 2. any known allergic reactions to selinexor or concomitant medication-related contra-indications to selinexor. 3. severe critical covid-19 infection defined as: 1. requiring invasive or non-invasive mechanical ventilation, ecmo 2. anticipated unlikely to survive within 48 hours 4. in the opinion of the investigator and primary oncologist, participation in the study would not be in the best interests of the participant 5. severe renal impairment defined as creatinine clearance (crcl) \< 20ml/min as calculated using the cockcroft gault formula 6. severe hepatic impairment defined as aspartate transaminase (ast) or alanine transaminase (alt) \> 5 x upper limit of normal (uln) arm 4 1. invasive mechanical ventilation or extracorporeal membrane oxygenation (ecmo) 2. history of pulmonary alveolar proteinosis (pap). 3. women of childbearing potential who are pregnant or breastfeeding. 4. known hypersensitivity to lenzilumab or any of its components. 5 .use of any fda-approved anti-il-6 therapy (eg. tocilizumab, sarilumab, siltukimab), anti-il-1 therapy (eg. anakinra, canakinumab) or kinase inhibitor (eg.baracitinib, ibrutinib, acalabrutinib) therapy to treat covid-19 within 8 weeks prior to randomization. any live vaccine within 8 weeks prior to randomisation. note that subjects receiving other fda-approved immunomodulators to treat underlying autoimmune disorders such as rheumatoid arthritis, psoriasis, ankylosing spondylitis, asthma, chronic obstructive pulmonary disease, atopic dermatitis, multiple sclerosis, etc. would not be excluded. participants on corticosteroids or dexamethasone are not excluded from the study. note: participants on convalescent plasma, remdesivir and/or hydroxychloroquine with or without azithromycin are not excluded from the study. 6. use of gm-csf agents (e.g., sargramostim) within 8 weeks prior to randomisation. 7. expected survival \< 24h in the opinion of the investigator. 8. any condition that, in the opinion of the investigator, is likely to interfere with the safety and efficacy of the study treatment or puts the subject at unacceptably high risk from the study. 9. participation in another interventional study of covid-19

arm 1 previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) have been exposed to a known covid-19 case within the last 72 hours, defined by the current department of health and human services such as household contact, 15 minutes of face to face exposure, 2 hours in close space. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study participant unable to return for regular follow-up life expectancy of less than 4 months participant already included in another intervention study on the prevention of covid-19 currently unwell with influenza-like symptoms - if participant is found to be covid-19 negative and becomes asymptomatic, they can be reconsidered for participation arm 2 previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study patient unable to return for follow-up life expectancy of less than 1 month patient already included in another intervention study on the prevention of covid-19 currently unwell with influenza-like symptoms arm 3 unable to take oral medication any known allergic reactions to selinexor or concomitant medication-related contra-indications to selinexor. severe critical covid-19 infection defined as: requiring invasive or non-invasive mechanical ventilation, ecmo anticipated unlikely to survive within 48 hours in the opinion of the investigator and primary oncologist, participation in the study would not be in the best interests of the participant severe renal impairment defined as creatinine clearance (crcl) < 20ml/min as calculated using the cockcroft gault formula severe hepatic impairment defined as aspartate transaminase (ast) or alanine transaminase (alt) > 5 x upper limit of normal (uln) arm 4 1. invasive mechanical ventilation or extracorporeal membrane oxygenation (ecmo) 2. history of pulmonary alveolar proteinosis (pap). 3. women of childbearing potential who are pregnant or breastfeeding. 4. known hypersensitivity to lenzilumab or any of its components. 5 .use of any fda-approved anti-il-6 therapy (eg. tocilizumab, sarilumab, siltukimab), anti-il-1 therapy (eg. anakinra, canakinumab) or kinase inhibitor (eg.baracitinib, ibrutinib, acalabrutinib) therapy to treat covid-19 within 8 weeks prior to randomization. any live vaccine within 8 weeks prior to randomisation. note that subjects receiving other fda-approved immunomodulators to treat underlying autoimmune disorders such as rheumatoid arthritis, psoriasis, ankylosing spondylitis, asthma, chronic obstructive pulmonary disease, atopic dermatitis, multiple sclerosis, etc. would not be excluded. participants on corticosteroids or dexamethasone are not excluded from the study. note: participants on convalescent plasma, remdesivir and/or hydroxychloroquine with or without azithromycin are not excluded from the study. 6. use of gm-csf agents (e.g., sargramostim) within 8 weeks prior to randomisation. 7. expected survival < 24h in the opinion of the investigator. 8. any condition that, in the opinion of the investigator, is likely to interfere with the safety and efficacy of the study treatment or puts the subject at unacceptably high risk from the study. 9. participation in another interventional study of covid-19

arm 1 previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) have been exposed to a known covid-19 case within the last 72 hours, defined by the current department of health and human services such as household contact, 15 minutes of face to face exposure, 2 hours in close space. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study participant unable to return for regular follow-up life expectancy of less than 4 months participant already included in another intervention study on the prevention of covid-19 currently unwell with influenza-like symptoms - if participant is found to be covid-19 negative and becomes asymptomatic, they can be reconsidered for participation arm 2 previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study patient unable to return for follow-up life expectancy of less than 1 month patient already included in another intervention study on the prevention of covid-19 currently unwell with influenza-like symptoms arm 3 unable to take oral medication any known allergic reactions to selinexor or concomitant medication-related contra-indications to selinexor. severe critical covid-19 infection defined as: requiring invasive or non-invasive mechanical ventilation, ecmo anticipated unlikely to survive within 48 hours in the opinion of the investigator and primary oncologist, participation in the study would not be in the best interests of the participant severe renal impairment defined as creatinine clearance (crcl) < 20ml/min as calculated using the cockcroft gault formula severe hepatic impairment defined as aspartate transaminase (ast) or alanine transaminase (alt) > 5 x upper limit of normal (uln) arm 4 1. invasive mechanical ventilation or extracorporeal membrane oxygenation (ecmo) 2. history of pulmonary alveolar proteinosis (pap). 3. women of childbearing potential who are pregnant or breastfeeding. 4. known hypersensitivity to lenzilumab or any of its components. 5 .use of any fda-approved anti-il-6 therapy (eg. tocilizumab, sarilumab, siltukimab), anti-il-1 therapy (eg. anakinra, canakinumab) or kinase inhibitor (eg.baracitinib, ibrutinib, acalabrutinib) therapy to treat covid-19 within 8 weeks prior to randomization. any live vaccine within 8 weeks prior to randomisation. note that subjects receiving other fda-approved immunomodulators to treat underlying autoimmune disorders such as rheumatoid arthritis, psoriasis, ankylosing spondylitis, asthma, chronic obstructive pulmonary disease, atopic dermatitis, multiple sclerosis, etc. would not be excluded. participants on corticosteroids or dexamethasone are not excluded from the study. note: participants on convalescent plasma, remdesivir and/or hydroxychloroquine with or without azithromycin are not excluded from the study. 6. use of gm-csf agents (e.g., sargramostim) within 8 weeks prior to randomisation. 7. expected survival < 24h in the opinion of the investigator. 8. any condition that, in the opinion of the investigator, is likely to interfere with the safety and efficacy of the study treatment or puts the subject at unacceptably high risk from the study. 9. participation in another interventional study of covid-19

-arm 1 1. previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) 2. have been exposed to a known covid-19 case within the last 72 hours, defined by the current department of health and human services such as household contact, 15 minutes of face to face exposure, 2 hours in close space. 3. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx 4. pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study 5. participant unable to return for regular follow-up 6. life expectancy of less than 4 months 7. participant already included in another intervention study on the prevention of covid-19 8. currently unwell with influenza-like symptoms - if participant is found to be covid-19 negative and becomes asymptomatic, they can be reconsidered for participation arm 2 1. previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) 2. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx 3. pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study 4. patient unable to return for follow-up 5. life expectancy of less than 1 month 6. patient already included in another intervention study on the prevention of covid-19 7. currently unwell with influenza-like symptoms arm 3 1. unable to take oral medication 2. any known allergic reactions to selinexor or concomitant medication-related contra-indications to selinexor. 3. severe critical covid-19 infection defined as: 1. requiring invasive or non-invasive mechanical ventilation, ecmo 2. anticipated unlikely to survive within 48 hours 4. in the opinion of the investigator and primary oncologist, participation in the study would not be in the best interests of the participant 5. severe renal impairment defined as creatinine clearance (crcl) < 20ml/min as calculated using the cockcroft gault formula 6. severe hepatic impairment defined as aspartate transaminase (ast) or alanine transaminase (alt) > 5 x upper limit of normal (uln) arm 4 1. invasive mechanical ventilation or extracorporeal membrane oxygenation (ecmo) 2. history of pulmonary alveolar proteinosis (pap). 3. women of childbearing potential who are pregnant or breastfeeding. 4. known hypersensitivity to lenzilumab or any of its components. 5 .use of any fda-approved anti-il-6 therapy (eg. tocilizumab, sarilumab, siltukimab), anti-il-1 therapy (eg. anakinra, canakinumab) or kinase inhibitor (eg.baracitinib, ibrutinib, acalabrutinib) therapy to treat covid-19 within 8 weeks prior to randomization. any live vaccine within 8 weeks prior to randomisation. note that subjects receiving other fda-approved immunomodulators to treat underlying autoimmune disorders such as rheumatoid arthritis, psoriasis, ankylosing spondylitis, asthma, chronic obstructive pulmonary disease, atopic dermatitis, multiple sclerosis, etc. would not be excluded. participants on corticosteroids or dexamethasone are not excluded from the study. note: participants on convalescent plasma, remdesivir and/or hydroxychloroquine with or without azithromycin are not excluded from the study. 6. use of gm-csf agents (e.g., sargramostim) within 8 weeks prior to randomisation. 7. expected survival < 24h in the opinion of the investigator. 8. any condition that, in the opinion of the investigator, is likely to interfere with the safety and efficacy of the study treatment or puts the subject at unacceptably high risk from the study. 9. participation in another interventional study of covid-19

-arm 1 1. previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) 2. have been exposed to a known covid-19 case within the last 72 hours, defined by the current department of health and human services such as household contact, 15 minutes of face to face exposure, 2 hours in close space. 3. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx 4. pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study 5. participant unable to return for regular follow-up 6. life expectancy of less than 4 months 7. participant already included in another intervention study on the prevention of covid-19 8. currently unwell with influenza-like symptoms - if participant is found to be covid-19 negative and becomes asymptomatic, they can be reconsidered for participation arm 2 1. previous diagnosis of covid-19 (microbiologically proven, either symptomatic or asymptomatic) 2. any contra-indication to intra-nasal ifn-a such as severe nasal bleeding requiring intervention, nasal malignancy, nasal deformity, radiotherapy to the nasopharynx and/or oropharynx 3. pregnant or breast-feeding women, or women who wish to become pregnant during the course of the study 4. patient unable to return for follow-up 5. life expectancy of less than 1 month 6. patient already included in another intervention study on the prevention of covid-19 7. currently unwell with influenza-like symptoms arm 3 1. unable to take oral medication 2. any known allergic reactions to selinexor or concomitant medication-related contra-indications to selinexor. 3. severe critical covid-19 infection defined as: 1. requiring invasive or non-invasive mechanical ventilation, ecmo 2. anticipated unlikely to survive within 48 hours 4. in the opinion of the investigator and primary oncologist, participation in the study would not be in the best interests of the participant 5. severe renal impairment defined as creatinine clearance (crcl) < 20ml/min as calculated using the cockcroft gault formula 6. severe hepatic impairment defined as aspartate transaminase (ast) or alanine transaminase (alt) > 5 x upper limit of normal (uln) arm 4 1. invasive mechanical ventilation or extracorporeal membrane oxygenation (ecmo) 2. history of pulmonary alveolar proteinosis (pap). 3. women of childbearing potential who are pregnant or breastfeeding. 4. known hypersensitivity to lenzilumab or any of its components. 5 .use of any fda-approved anti-il-6 therapy (eg. tocilizumab, sarilumab, siltukimab), anti-il-1 therapy (eg. anakinra, canakinumab) or kinase inhibitor (eg.baracitinib, ibrutinib, acalabrutinib) therapy to treat covid-19 within 8 weeks prior to randomization. any live vaccine within 8 weeks prior to randomisation. note that subjects receiving other fda-approved immunomodulators to treat underlying autoimmune disorders such as rheumatoid arthritis, psoriasis, ankylosing spondylitis, asthma, chronic obstructive pulmonary disease, atopic dermatitis, multiple sclerosis, etc. would not be excluded. participants on corticosteroids or dexamethasone are not excluded from the study. note: participants on convalescent plasma, remdesivir and/or hydroxychloroquine with or without azithromycin are not excluded from the study. 6. use of gm-csf agents (e.g., sargramostim) within 8 weeks prior to randomisation. 7. expected survival < 24h in the opinion of the investigator. 8. any condition that, in the opinion of the investigator, is likely to interfere with the safety and efficacy of the study treatment or puts the subject at unacceptably high risk from the study. 9. participation in another interventional study of covid-19