Master Protocol: Patients are eligible to be included in the study only if all of the following criteria apply (as well as all criteria from the appropriate candidate-specific trial protocol): 1. Adults (≥18 years) with laboratory-confirmed* SARS-CoV-2 infection (PCR) 2. Ability to provide informed consent signed by study patient or legally acceptable representative 3. Women of childbearing potential (WOCBP) and male patients who are sexually active with WOCBP must agree to use a highly effective method of contraception from the first administration of trial treatment, throughout trial treatment and for the duration outlined in the candidate-specific trial protocol after the last dose of trial treatment *If any CSTs are included in the community setting, the CST protocol will clarify whether patients with suspected SARS-CoV-2 infection are also eligible. Standard additional criteria that may be applied per candidate-specific trial protocol: Group A (severe disease) Patients with clinical status of Grades 5 (hospitalised, oxygen by mask or nasal prongs), 6 (hospitalised, non-invasive ventilation or high flow oxygen), 7 (hospitalised, intubation and mechanical ventilation, pO2/FiO2 ≥150 or SpO2/FiO2 ≥200), 8 (hospitalised mechanical ventilation pO2/FiO2 <150 (SpO2/FiO2 <200) or vasopressors or 9 (hospitalised, mechanical ventilation pO2/FiO2 <150 and vasopressors, dialysis or ECMO) (as defined by the WHO Clinical Progression Scale. Group B (mild-moderate disease) 4b. Ambulant or hospitalised patients with peripheral capillary oxygen saturation (SpO2) >94% RA. Nomacopan Candidate-Specific Trial: Additional inclusion criteria specific to this CST are: 1. Adults (≥18 years) with laboratory-confirmed SARS-CoV-2 infection (PCR) who are within 5 days of symptom onset. 4. A score of grade 4, 5, 6 or 7 on the 9-Point Ordinal Scale* Grade 6 and 7 will only be accepted when second cohort open to recruitment. CST-2 (EIDD-2801) additional inclusion criteria: 5. Has signs or symptoms of COVID-19 that began within 5 days of the planned first dose of study drug. 6. Is in generally good health (except for current respiratory infection) and is free of uncontrolled chronic conditions. 7. Is willing and able to comply with all study procedures and attending weekly clinic visits through the 4th week. 8. Has someone, aged ≥ 16 living in the same household during the dosing period.

Master Protocol: Patients are eligible to be included in the study only if all of the following criteria apply (as well as all criteria from the appropriate candidate-specific trial protocol): 1. Adults (≥18 years) with laboratory-confirmed* SARS-CoV-2 infection (PCR) 2. Ability to provide informed consent signed by study patient or legally acceptable representative 3. Women of childbearing potential (WOCBP) and male patients who are sexually active with WOCBP must agree to use a highly effective method of contraception from the first administration of trial treatment, throughout trial treatment and for the duration outlined in the candidate-specific trial protocol after the last dose of trial treatment *If any CSTs are included in the community setting, the CST protocol will clarify whether patients with suspected SARS-CoV-2 infection are also eligible. Standard additional criteria that may be applied per candidate-specific trial protocol: Group A (severe disease) Patients with clinical status of Grades 5 (hospitalised, oxygen by mask or nasal prongs), 6 (hospitalised, non-invasive ventilation or high flow oxygen), 7 (hospitalised, intubation and mechanical ventilation, pO2/FiO2 ≥150 or SpO2/FiO2 ≥200), 8 (hospitalised mechanical ventilation pO2/FiO2 <150 (SpO2/FiO2 <200) or vasopressors or 9 (hospitalised, mechanical ventilation pO2/FiO2 <150 and vasopressors, dialysis or ECMO) (as defined by the WHO Clinical Progression Scale. Group B (mild-moderate disease) 4b. Ambulant or hospitalised patients with peripheral capillary oxygen saturation (SpO2) >94% RA. Nomacopan Candidate-Specific Trial: Additional inclusion criteria specific to this CST are: 1. Adults (≥18 years) with laboratory-confirmed SARS-CoV-2 infection (PCR) who are within 5 days of symptom onset. 4. A score of grade 4, 5, 6 or 7 on the 9-Point Ordinal Scale* Grade 6 and 7 will only be accepted when second cohort open to recruitment. CST-2 (EIDD-2801) additional inclusion criteria: 5. Has signs or symptoms of COVID-19 that began within 5 days of the planned first dose of study drug. 6. Is in generally good health (except for current respiratory infection) and is free of uncontrolled chronic conditions. 7. Is willing and able to comply with all study procedures and attending weekly clinic visits through the 4th week. 8. Has someone, aged ≥ 16 living in the same household during the dosing period.