1) Admitted to hospital due to the severity of their COVID-19 <br/ > <br/ >2) Positive virus test for SARS-CoV-2 using a validated molecular assay or antigen assay. Patients who had positive virus test for SARS-CoV-2 prior to hospitalisation will be randomised no later than 48 hours after hospital admission. If the virus test was performed more than 96 hours prior to hospitalisation, the test will have to be repeated in the hospital prior to randomisation. Only patients whose repeated virus test is positive will be randomised, no later than 48 hours after confirmation of SARS-CoV-2 infection. Patients who had positive virus test for SARS-CoV-2 after hospitalisation will be randomised no later than 48 hours after confirmation of SARS-CoV-2 infection <br/ > <br/ >3) Require oxygen therapy via nasal prongs or mask (OSCI score of 4) <br/ > <br/ >4) Provided informed consent <br/ > <br/ >5) Female patients must be greater than or equals to 1 year post-menopausal, surgically sterile, or using a protocol defined highly effective method of contraception <br/ > <br/ >6) Women should have been stable on their chosen method of birth control for a minimum of 3 months before entering the trial and should continue with birth control for 1 month after the last dose of inhaled interferon-beta (IFN-beta 1a)/matching placebo. In addition to the highly effective method of contraception (except for the practice of total sexual abstinence), a condom (in United Kingdom with spermicides) should be used by the male partner for sexual intercourse from randomisation (Visit 2) and for 1 month after the last dose of inhaled IFN-beta1a/matching placebo to prevent pregnancy <br/ > <br/ >7) Women not of childbearing potential are defined as women who are either permanently sterilized (hysterectomy, bilateral oophorectomy, or bilateral salpingectomy), or who are postmenopausal. Women will be considered post-menopausal if they have been amenorrhoeic for 12 months prior to the planned date of randomisation without an alternative medical cause. The following age specific requirements apply: women less than 50 years old will be considered post-menopausal if they have been amenorrhoeic for 12 months or more following cessation of exogenous hormonal treatment and if follicle stimulating hormone (FSH) levels are in the postmenopausal range, women greater than or equals to 50 years old will be considered post-menopausal if they have been amenorrhoeic for 12 months or more following cessation of all exogenous hormonal treatment. If, in the setting of the pandemic, the use of an acceptable birth control method is not possible, the decision to enroll a woman of childbearing potential should be based on the benefit-risk for the patient, which should be discussed with the patient at the time of the informed consent

1) Admitted to hospital due to the severity of their COVID-19 <br/ > <br/ >2) Positive virus test for SARS-CoV-2 using a validated molecular assay or antigen assay. Patients who had positive virus test for SARS-CoV-2 prior to hospitalisation will be randomised no later than 48 hours after hospital admission. If the virus test was performed more than 96 hours prior to hospitalisation, the test will have to be repeated in the hospital prior to randomisation. Only patients whose repeated virus test is positive will be randomised, no later than 48 hours after confirmation of SARS-CoV-2 infection. Patients who had positive virus test for SARS-CoV-2 after hospitalisation will be randomised no later than 48 hours after confirmation of SARS-CoV-2 infection <br/ > <br/ >3) Require oxygen therapy via nasal prongs or mask (OSCI score of 4) <br/ > <br/ >4) Provided informed consent <br/ > <br/ >5) Female patients must be greater than or equals to 1 year post-menopausal, surgically sterile, or using a protocol defined highly effective method of contraception <br/ > <br/ >6) Women should have been stable on their chosen method of birth control for a minimum of 3 months before entering the trial and should continue with birth control for 1 month after the last dose of inhaled interferon-beta (IFN-beta 1a)/matching placebo. In addition to the highly effective method of contraception (except for the practice of total sexual abstinence), a condom (in United Kingdom with spermicides) should be used by the male partner for sexual intercourse from randomisation (Visit 2) and for 1 month after the last dose of inhaled IFN-beta1a/matching placebo to prevent pregnancy <br/ > <br/ >7) Women not of childbearing potential are defined as women who are either permanently sterilized (hysterectomy, bilateral oophorectomy, or bilateral salpingectomy), or who are postmenopausal. Women will be considered post-menopausal if they have been amenorrhoeic for 12 months prior to the planned date of randomisation without an alternative medical cause. The following age specific requirements apply: women less than 50 years old will be considered post-menopausal if they have been amenorrhoeic for 12 months or more following cessation of exogenous hormonal treatment and if follicle stimulating hormone (FSH) levels are in the postmenopausal range, women greater than or equals to 50 years old will be considered post-menopausal if they have been amenorrhoeic for 12 months or more following cessation of all exogenous hormonal treatment. If, in the setting of the pandemic, the use of an acceptable birth control method is not possible, the decision to enroll a woman of childbearing potential should be based on the benefit-risk for the patient, which should be discussed with the patient at the time of the informed consent

1) Admitted to hospital due to the severity of their COVID-19 <br/ > <br/ >2) Positive virus test for SARS-CoV-2 using a validated molecular assay or antigen assay. Patients who had positive virus test for SARS-CoV-2 prior to hospitalisation will be randomised no later than 48 hours after hospital admission. If the virus test was performed more than 96 hours prior to hospitalisation, the test will have to be repeated in the hospital prior to randomisation. Only patients whose repeated virus test is positive will be randomised, no later than 48 hours after confirmation of SARS-CoV-2 infection. Patients who had positive virus test for SARS-CoV-2 after hospitalisation will be randomised no later than 48 hours after confirmation of SARS-CoV-2 infection <br/ > <br/ >3) Require oxygen therapy via nasal prongs or mask (OSCI score of 4) <br/ > <br/ >4) Provided informed consent <br/ > <br/ >5) Female patients must be greater than or equals to 1 year post-menopausal, surgically sterile, or using a protocol defined highly effective method of contraception <br/ > <br/ >6) Women should have been stable on their chosen method of birth control for a minimum of 3 months before entering the trial and should continue with birth control for 1 month after the last dose of inhaled interferon-beta (IFN-beta 1a)/matching placebo. In addition to the highly effective method of contraception (except for the practice of total sexual abstinence), a condom (in United Kingdom with spermicides) should be used by the male partner for sexual intercourse from randomisation (Visit 2) and for 1 month after the last dose of inhaled IFN-beta1a/matching placebo to prevent pregnancy <br/ > <br/ >7) Women not of childbearing potential are defined as women who are either permanently sterilized (hysterectomy, bilateral oophorectomy, or bilateral salpingectomy), or who are postmenopausal. Women will be considered post-menopausal if they have been amenorrhoeic for 12 months prior to the planned date of randomisation without an alternative medical cause. The following age specific requirements apply: women less than 50 years old will be considered post-menopausal if they have been amenorrhoeic for 12 months or more following cessation of exogenous hormonal treatment and if follicle stimulating hormone (FSH) levels are in the postmenopausal range, women greater than or equals to 50 years old will be considered post-menopausal if they have been amenorrhoeic for 12 months or more following cessation of all exogenous hormonal treatment. If, in the setting of the pandemic, the use of an acceptable birth control method is not possible, the decision to enroll a woman of childbearing potential should be based on the benefit-risk for the patient, which should be discussed with the patient at the time of the informed consent

1) Admitted to hospital due to the severity of their COVID-19 <br/ > <br/ >2) Positive virus test for SARS-CoV-2 using a validated molecular assay or antigen assay. Patients who had positive virus test for SARS-CoV-2 prior to hospitalisation will be randomised no later than 48 hours after hospital admission. If the virus test was performed more than 96 hours prior to hospitalisation, the test will have to be repeated in the hospital prior to randomisation. Only patients whose repeated virus test is positive will be randomised, no later than 48 hours after confirmation of SARS-CoV-2 infection. Patients who had positive virus test for SARS-CoV-2 after hospitalisation will be randomised no later than 48 hours after confirmation of SARS-CoV-2 infection <br/ > <br/ >3) Require oxygen therapy via nasal prongs or mask (OSCI score of 4) <br/ > <br/ >4) Provided informed consent <br/ > <br/ >5) Female patients must be greater than or equals to 1 year post-menopausal, surgically sterile, or using a protocol defined highly effective method of contraception <br/ > <br/ >6) Women should have been stable on their chosen method of birth control for a minimum of 3 months before entering the trial and should continue with birth control for 1 month after the last dose of inhaled interferon-beta (IFN-beta 1a)/matching placebo. In addition to the highly effective method of contraception (except for the practice of total sexual abstinence), a condom (in United Kingdom with spermicides) should be used by the male partner for sexual intercourse from randomisation (Visit 2) and for 1 month after the last dose of inhaled IFN-beta1a/matching placebo to prevent pregnancy <br/ > <br/ >7) Women not of childbearing potential are defined as women who are either permanently sterilized (hysterectomy, bilateral oophorectomy, or bilateral salpingectomy), or who are postmenopausal. Women will be considered post-menopausal if they have been amenorrhoeic for 12 months prior to the planned date of randomisation without an alternative medical cause. The following age specific requirements apply: women less than 50 years old will be considered post-menopausal if they have been amenorrhoeic for 12 months or more following cessation of exogenous hormonal treatment and if follicle stimulating hormone (FSH) levels are in the postmenopausal range, women greater than or equals to 50 years old will be considered post-menopausal if they have been amenorrhoeic for 12 months or more following cessation of all exogenous hormonal treatment. If, in the setting of the pandemic, the use of an acceptable birth control method is not possible, the decision to enroll a woman of childbearing potential should be based on the benefit-risk for the patient, which should be discussed with the patient at the time of the informed consent