(1) Fever (more than or equal to 37.5 degree celsius) more than 10 days after the onset of fever (2) Patients who have the following clinical symptoms 1), 2) and 3) 1) SpO2 less than 95% without oxygen therapy 2) Respiratory rate more than 24 breath/min 3) Blood pressure (SBP/DBP) less than 90/60 mmHg (3) Patients who show increased procalcitonin levels before the start of study drug administration and are suspected to have concurrent bacterial infection (4) Patients with suspected concomitant fungal infections prior to initiation of study drug (e.g., 1-3-beta glucan: 30 pg / ml or higher) (5) Patients who show, for example, abnormal NT-pro BNP levels (100 pg/mL or higher etc.) and/or are suspected to have concurrent congestive heart failure (6) Patients with severe hepatic impairment equivalent to Grade C on Child-Pugh classification (7) Patients with renal impairment requiring dialysis (8) Patients with disturbed consciousness such as disturbed orientation (9) Pregnant or possibly pregnant patients (10) Female patients who are unable to consent to contraceptive use of oral contraceptives, mechanical contraceptives such as intrauterine devices or barrier devices (pessaries, condoms), or a combination of these devices from the start of favipiravir administration to 14 days after the end of favipiravir administration. (11) Male patients whose partner cannot agree to use the contraception method described in (10) above (12) Patients who cannot consent to the use of condoms from the start of favipiravir administration to 7 days after the end of favipiravir administration (13) Patients with hereditary xanthinuria (14) Patients who have previously ever been diagnosed with hypouricemia (less than 1 mg/dL) or xanthine urinary calculi (15) Patients receiving immunosuppressants (16) Patients who have received interferon-alpha or drugs with reported antiviral activity against SARS-CoV-2 (hydroxychloroquine sulfate, chloroquine phosphate, lopinavir-ritonavir combination, ciclesonide, nafamostat mesylate, camostat mesylate, remdesivir, etc.) within 9 days after fever (37.5 degree celsius or more) or symptoms of COVID-19. (17) Patients in whom this episode of infection is a recurrence or reinfection of SARS-CoV-2 infection (18) Patients who have previously received favipiravir (T-705a) (19) Other patients judged ineligible by the investigator, sub-investigator, or assigned physician (20) Patients who must take the following medication, pyrazinamide, repaglinide, theophylline, famciclovir and sulindac (21) Female patients who intend to have breastfeeding during starting favipiravir administration and until 7 days after stop favipiravir administration

(1) Fever (more than or equal to 37.5 degree celsius) more than 10 days after the onset of fever (2) Patients who have the following clinical symptoms 1), 2) and 3) 1) SpO2 less than 95% without oxygen therapy 2) Respiratory rate more than 24 breath/min 3) Blood pressure (SBP/DBP) less than 90/60 mmHg (3) Patients who show increased procalcitonin levels before the start of study drug administration and are suspected to have concurrent bacterial infection (4) Patients with suspected concomitant fungal infections prior to initiation of study drug (e.g., 1-3-beta glucan: 30 pg / ml or higher) (5) Patients who show, for example, abnormal NT-pro BNP levels (100 pg/mL or higher etc.) and/or are suspected to have concurrent congestive heart failure (6) Patients with severe hepatic impairment equivalent to Grade C on Child-Pugh classification (7) Patients with renal impairment requiring dialysis (8) Patients with disturbed consciousness such as disturbed orientation (9) Pregnant or possibly pregnant patients (10) Female patients who are unable to consent to contraceptive use of oral contraceptives, mechanical contraceptives such as intrauterine devices or barrier devices (pessaries, condoms), or a combination of these devices from the start of favipiravir administration to 14 days after the end of favipiravir administration. (11) Male patients whose partner cannot agree to use the contraception method described in (10) above (12) Patients who cannot consent to the use of condoms from the start of favipiravir administration to 7 days after the end of favipiravir administration (13) Patients with hereditary xanthinuria (14) Patients who have previously ever been diagnosed with hypouricemia (less than 1 mg/dL) or xanthine urinary calculi (15) Patients receiving immunosuppressants (16) Patients who have received interferon-alpha or drugs with reported antiviral activity against SARS-CoV-2 (hydroxychloroquine sulfate, chloroquine phosphate, lopinavir-ritonavir combination, ciclesonide, nafamostat mesylate, camostat mesylate, remdesivir, etc.) within 9 days after fever (37.5 degree celsius or more) or symptoms of COVID-19. (17) Patients in whom this episode of infection is a recurrence or reinfection of SARS-CoV-2 infection (18) Patients who have previously received favipiravir (T-705a) (19) Other patients judged ineligible by the investigator, sub-investigator, or assigned physician (20) Patients who must take the following medication, pyrazinamide, repaglinide, theophylline, famciclovir and sulindac (21) Female patients who intend to have breastfeeding during starting favipiravir administration and until 7 days after stop favipiravir administration

(1) Fever (37.5°C) more than 10 days after the onset of fever (2) Patients with SpO2 less than 95% without oxygen therapy (3) Patients who show increased procalcitonin levels before the start of study drug administration and are suspected to have concurrent bacterial infection (4) Patients with suspected concomitant fungal infections prior to initiation of study drug (e.g.&#44, 1&#45,3&#45,β glucan: 30 pg / ml or higher) (5) Patients who show&#44, for example&#44, abnormal NT&#45,pro BNP levels (100 pg/mL or higher etc.) and/or are suspected to have concurrent congestive heart failure (6) Patients with severe hepatic impairment equivalent to Grade C on Child&#45,Pugh classification (7) Patients with renal impairment requiring dialysis (8) Patients with disturbed consciousness such as disturbed orientation (9) Pregnant or possibly pregnant patients (10) Female patients who are unable to consent to contraceptive use of oral contraceptives&#44, mechanical contraceptives such as intrauterine devices or barrier devices (pessaries&#44, condoms)&#44, or a combination of these devices from the start of favipiravir administration to 7 days after the end of favipiravir administration. (11) Male patients whose partner cannot agree to use the contraception method described in (10) above (12) Patients who cannot consent to the use of condoms from the start of favipiravir administration to 7 days after the end of favipiravir administration (13) Patients with hereditary xanthinuria (14) Patients who have previously ever been diagnosed with hypouricemia (< 1 mg/dL) or xanthine urinary calculi (15) Patients with a history of gout or on treatment for gout or hyperuricemia (16) Patients receiving immunosuppressants (17) Patients who have received interferon&#45,alpha or drugs with reported antiviral activity against SARS&#45,CoV&#45,2 (hydroxychloroquine sulfate&#44, chloroquine phosphate&#44, lopinavir&#45,ritonavir combination&#44, ciclesonide&#44, nafamostat mesylate&#44, camostat mesylate&#44, remdesivir&#44, etc.) within 9 days after fever (37.5°C or more). (18) Patients in whom this episode of infection is a recurrence or reinfection of SARS&#45,CoV&#45,2 infection (19) Patients who have previously received favipiravir (T&#45,705a) (20) Other patients judged ineligible by the investigator&#44, sub&#45,investigator&#44, or assigned physician

(1) Fever (37.5°C) more than 10 days after the onset of fever (2) Patients with SpO2 less than 95% without oxygen therapy (3) Patients who show increased procalcitonin levels before the start of study drug administration and are suspected to have concurrent bacterial infection (4) Patients with suspected concomitant fungal infections prior to initiation of study drug (e.g.&#44, 1&#45,3&#45,β glucan: 30 pg / ml or higher) (5) Patients who show&#44, for example&#44, abnormal NT&#45,pro BNP levels (100 pg/mL or higher etc.) and/or are suspected to have concurrent congestive heart failure (6) Patients with severe hepatic impairment equivalent to Grade C on Child&#45,Pugh classification (7) Patients with renal impairment requiring dialysis (8) Patients with disturbed consciousness such as disturbed orientation (9) Pregnant or possibly pregnant patients (10) Female patients who are unable to consent to contraceptive use of oral contraceptives&#44, mechanical contraceptives such as intrauterine devices or barrier devices (pessaries&#44, condoms)&#44, or a combination of these devices from the start of favipiravir administration to 7 days after the end of favipiravir administration. (11) Male patients whose partner cannot agree to use the contraception method described in (10) above (12) Patients who cannot consent to the use of condoms from the start of favipiravir administration to 7 days after the end of favipiravir administration (13) Patients with hereditary xanthinuria (14) Patients who have previously ever been diagnosed with hypouricemia (< 1 mg/dL) or xanthine urinary calculi (15) Patients with a history of gout or on treatment for gout or hyperuricemia (16) Patients receiving immunosuppressants (17) Patients who have received interferon&#45,alpha or drugs with reported antiviral activity against SARS&#45,CoV&#45,2 (hydroxychloroquine sulfate&#44, chloroquine phosphate&#44, lopinavir&#45,ritonavir combination&#44, ciclesonide&#44, nafamostat mesylate&#44, camostat mesylate&#44, remdesivir&#44, etc.) within 9 days after fever (37.5°C or more). (18) Patients in whom this episode of infection is a recurrence or reinfection of SARS&#45,CoV&#45,2 infection (19) Patients who have previously received favipiravir (T&#45,705a) (20) Other patients judged ineligible by the investigator&#44, sub&#45,investigator&#44, or assigned physician

(1) Fever (37.5°C) more than 10 days after the onset of fever (2) Patients with SpO2 less than 95% without oxygen therapy (3) Patients who show increased procalcitonin levels before the start of study drug administration and are suspected to have concurrent bacterial infection (4) Patients with suspected concomitant fungal infections prior to initiation of study drug (e.g., 1-3-β glucan: 30 pg / ml or higher) (5) Patients who show, for example, abnormal NT-pro BNP levels (100 pg/mL or higher etc.) and/or are suspected to have concurrent congestive heart failure (6) Patients with severe hepatic impairment equivalent to Grade C on Child-Pugh classification (7) Patients with renal impairment requiring dialysis (8) Patients with disturbed consciousness such as disturbed orientation (9) Pregnant or possibly pregnant patients (10) Female patients who are unable to consent to contraceptive use of oral contraceptives, mechanical contraceptives such as intrauterine devices or barrier devices (pessaries, condoms), or a combination of these devices from the start of favipiravir administration to 7 days after the end of favipiravir administration. (11) Male patients whose partner cannot agree to use the contraception method described in (10) above (12) Patients who cannot consent to the use of condoms from the start of favipiravir administration to 7 days after the end of favipiravir administration (13) Patients with hereditary xanthinuria (14) Patients who have previously ever been diagnosed with hypouricemia (< 1 mg/dL) or xanthine urinary calculi (15) Patients with a history of gout or on treatment for gout or hyperuricemia (16) Patients receiving immunosuppressants (17) Patients who have received interferon-alpha or drugs with reported antiviral activity against SARS-CoV-2 (hydroxychloroquine sulfate, chloroquine phosphate, lopinavir-ritonavir combination, ciclesonide, nafamostat mesylate, camostat mesylate, remdesivir, etc.) within 9 days after fever (37.5°C or more). (18) Patients in whom this episode of infection is a recurrence or reinfection of SARS-CoV-2 infection (19) Patients who have previously received favipiravir (T-705a) (20) Other patients judged ineligible by the investigator, sub-investigator, or assigned physician

(1) Fever (37.5°C) more than 10 days after the onset of fever (2) Patients with SpO2 less than 95% without oxygen therapy (3) Patients who show increased procalcitonin levels before the start of study drug administration and are suspected to have concurrent bacterial infection (4) Patients with suspected concomitant fungal infections prior to initiation of study drug (e.g., 1-3-β glucan: 30 pg / ml or higher) (5) Patients who show, for example, abnormal NT-pro BNP levels (100 pg/mL or higher etc.) and/or are suspected to have concurrent congestive heart failure (6) Patients with severe hepatic impairment equivalent to Grade C on Child-Pugh classification (7) Patients with renal impairment requiring dialysis (8) Patients with disturbed consciousness such as disturbed orientation (9) Pregnant or possibly pregnant patients (10) Female patients who are unable to consent to contraceptive use of oral contraceptives, mechanical contraceptives such as intrauterine devices or barrier devices (pessaries, condoms), or a combination of these devices from the start of favipiravir administration to 7 days after the end of favipiravir administration. (11) Male patients whose partner cannot agree to use the contraception method described in (10) above (12) Patients who cannot consent to the use of condoms from the start of favipiravir administration to 7 days after the end of favipiravir administration (13) Patients with hereditary xanthinuria (14) Patients who have previously ever been diagnosed with hypouricemia (< 1 mg/dL) or xanthine urinary calculi (15) Patients with a history of gout or on treatment for gout or hyperuricemia (16) Patients receiving immunosuppressants (17) Patients who have received interferon-alpha or drugs with reported antiviral activity against SARS-CoV-2 (hydroxychloroquine sulfate, chloroquine phosphate, lopinavir-ritonavir combination, ciclesonide, nafamostat mesylate, camostat mesylate, remdesivir, etc.) within 9 days after fever (37.5°C or more). (18) Patients in whom this episode of infection is a recurrence or reinfection of SARS-CoV-2 infection (19) Patients who have previously received favipiravir (T-705a) (20) Other patients judged ineligible by the investigator, sub-investigator, or assigned physician