Current exclusion criteria as of 21/03/2022: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment 4. History of acute or chronic gout, or hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe hepatic impairment, defined as > Child-Pugh grade A, AST or ALT >5 x ULN or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. More than 7 days since onset of COVID-19 symptoms 9. Unable to discontinue contra-indicated concomitant medications 10. Eligible to directly access anti-viral or neutralising monoclonal antibody therapies for COVID19, as defined by UK clinical commissioning guidance at the point of assessment _____ Previous exclusion criteria as of 11/10/2021: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe hepatic impairment, defined as > Child-Pugh grade A, AST or ALT >5 x ULN or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. More than 7 days since onset of COVID-19 symptoms 9. Unable to discontinue contra-indicated concomitant medications (section 6.7) _____ Previous exclusion criteria: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe co-morbidities including patients with severe hepatic impairment, defined as: greater than Child-Pugh grade A, AST or ALT >5 x ULN, or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. >96 h since first positive COVID19 test sample was taken 9. Unable to discontinue contra-indicated concomitant medications

Current exclusion criteria as of 21/03/2022: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment 4. History of acute or chronic gout, or hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe hepatic impairment, defined as > Child-Pugh grade A, AST or ALT >5 x ULN or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. More than 7 days since onset of COVID-19 symptoms 9. Unable to discontinue contra-indicated concomitant medications 10. Eligible to directly access anti-viral or neutralising monoclonal antibody therapies for COVID19, as defined by UK clinical commissioning guidance at the point of assessment _____ Previous exclusion criteria as of 11/10/2021: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe hepatic impairment, defined as > Child-Pugh grade A, AST or ALT >5 x ULN or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. More than 7 days since onset of COVID-19 symptoms 9. Unable to discontinue contra-indicated concomitant medications (section 6.7) _____ Previous exclusion criteria: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe co-morbidities including patients with severe hepatic impairment, defined as: greater than Child-Pugh grade A, AST or ALT >5 x ULN, or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. >96 h since first positive COVID19 test sample was taken 9. Unable to discontinue contra-indicated concomitant medications

Current exclusion criteria as of 11/10/2021: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe hepatic impairment, defined as > Child-Pugh grade A, AST or ALT >5 x ULN or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. More than 7 days since onset of COVID-19 symptoms 9. Unable to discontinue contra-indicated concomitant medications (section 6.7) Previous exclusion criteria: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe co-morbidities including patients with severe hepatic impairment, defined as: greater than Child-Pugh grade A, AST or ALT >5 x ULN, or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. >96 h since first positive COVID19 test sample was taken 9. Unable to discontinue contra-indicated concomitant medications

Current exclusion criteria as of 11/10/2021: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe hepatic impairment, defined as > Child-Pugh grade A, AST or ALT >5 x ULN or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. More than 7 days since onset of COVID-19 symptoms 9. Unable to discontinue contra-indicated concomitant medications (section 6.7) Previous exclusion criteria: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Childbearing potential, or, with partners of childbearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe co-morbidities including patients with severe hepatic impairment, defined as: greater than Child-Pugh grade A, AST or ALT >5 x ULN, or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. >96 h since first positive COVID19 test sample was taken 9. Unable to discontinue contra-indicated concomitant medications

1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Child bearing potential, or, with partners of child bearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe co-morbidities including patients with severe hepatic impairment, defined as: greater than Child-Pugh grade A, AST or ALT >5 x ULN, or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. >96 h since first positive COVID19 test sample was taken 9. Unable to discontinue contra-indicated concomitant medications

1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Child bearing potential, or, with partners of child bearing potential, who do not agree to the use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment. 4. History of hereditary xanthinuria 5. Judged to be ineligible by the principal investigator or sub-investigator 6. Known hypersensitivity to favipiravir, its metabolites, or its excipients 7. Severe co-morbidities including patients with severe hepatic impairment, defined as: greater than Child-Pugh grade A, AST or ALT >5 x ULN, or AST or ALT >3 x ULN and Total Bilirubin >2 x ULN 8. >96 h since first positive COVID19 test sample was taken 9. Unable to discontinue contra-indicated concomitant medications