UMIT-2 - Adaptive Phase IIb Platform Trial to Determine the Efficacy and Safety of Therapeutics for CCHF

Inclusion Criteria: Adult in-patients (≥18 years) Laboratory confirmed CCHF infection by positive polymerase chain reaction (PCR) test within 5 days prior to randomisation Capacity to provide informed consent signed by study patient or legally acceptable representative (for illiterate individuals). Women of childbearing potential (WOCBP) and male patients who are sexually active with WOCBP must agree to use a highly effective method of contraception (as outlined in section 5.4 below) from the first administration of trial treatment, throughout trial treatment and for the duration outlined in trial protocol as well as addition 14 days for women and 7 days for men after the last dose of trial treatment. Severity Grading System (SGS) for CCHF - mild/moderate. Less than or equal to 7 days from onset of CCHF symptoms Willingness to participate in the full protocol Requirement to be hospitalised for treatment- Exclusion Criteria: Stage 4 severe chronic kidney disease or requiring dialysis (i.e., estimated glomerular filtration (eGFR) rate \<30 mL/min/1.73 m2) Pregnant or breast feeding Anticipated transfer to another hospital which is not a study site within 72 hours Known Allergy to any study medication Patients participating in another clinical trial of an investigational medicinal product (CTIMP) within the last 30 days. Previous intolerance of Favipiravir or Ribavirin Any participants deemed not suitable, based on investigators opinion. Patients taking the drugs listed below within 30 days or 5 times the half-life (whichever is longer) of enrolment: Pyrazinamide: Pyrazinamide administration with favipiravir examined possible renal urate transporter interactions. Pyrazinamide increased blood uric acid levels 2 to 9 mg/dL over baseline. The addition of favipiravir increased blood uric acid levels 4 to 11 mg/dL over baseline, indicating a moderate additive effect. Repaglinide: Favipiravir administration with repaglinide, an anti-diabetic agent that is extensively metabolized by CYP2C8 and CYP3A4, increased repaglinide plasma AUC 30 to 50% due to inhibition of CYP2C8. Theophylline: Theophylline administration with favipiravir increases plasma Cmax and AUC of favipiravir through xanthine oxidase (XO) interaction. The primary metabolite of theophylline is known to be metabolized by XO which is partially involved in metabolism of favipiravir. Famciclovir, Sulindac: Famciclovir and Sulindac are converted to active metabolite by Aldehyde Oxidase (AO). Favipiravir inhibits AO and decrease the concentration of active metabolite of Famciclovir and Sulindac. Paracetamol: Coadministration of paracetamol (650 mg once daily) and favipiravir (1200 mg twice daily or 800 mg twice daily) increased paracetamol Cmax and AUC by 3% and 16% (1200 mg doses) and by 8% and 14% (800 mg doses). In the UMIT-2 trial after screening and randomisation the daily dose of paracetamol in adults should be no more than 3000 mg/day (rather than 4000 mg/day) -