ISTH/ANRS 0409s INTEGRATE Lassa Fever Study

1. General Inclusion criteria * Clinical disease with signs and symptoms suggestive for LF * Positive plasma LASV RT-PCR * Participant requires hospitalization per the local guidelines * Participant or their legally authorized representative is able and willing to sign the informed consent Exclusion criteria * Unwilling to provide informed consent * Positive pregnancy test * Unwilling to provide informed consent * History of allergic reaction or other contra-indication to ribavirin according to the Reference safety document * Received drug therapy for Lassa fever (excluding supportive care) prior to inclusion * Has received a vaccine against LF 2. Sub-protocols 2.1 Favipiravir high dose sub-protocol Inclusion criteria • Age ≥ 18 years old Exclusion criteria • Pregnancy (evidenced by positive urine pregnancy test in women of child-bearing potential) * Treatment contraindicated with favipiravir according to the Reference safety document * Pre-existing liver failure * Severe symptomatic gout/hyperuricemia * History of QT prolongation or arrhythmia or other cardiac disorders * PR interval ≥ 200 ms * Hypersensitivity to excipients * Inability to take oral drug (e.g. encephalopathy, severe vomiting) 2.2. Favipiravir-Ribavirin sub-protocol Inclusion criteria • Age ≥ 18 years old Exclusion criteria * Pregnancy (evidenced by positive urine pregnancy test in women of child-bearing potential) * Treatment contraindicated with favipiravir according to the Reference safety document * Pre-existing liver failure * Severe symptomatic gout/hyperuricemia * History of QT prolongation or arrhythmia or other cardiac disorders * PR interval ≥ 200 ms * Hypersensitivity to excipients * Inability to take oral drug (e.g. encephalopathy, severe vomiting) 2.3. Dexamethasone sub-protocol Inclusion criteria • Age ≥ 12 years old Exclusion criteria • Pregnancy (evidenced by positive urine pregnancy test in women of child-bearing potential) • Known intolerance and contra-indications to ribavirin or dexamethasone • Patients who already received a corticosteroid within the preceding 7 days 2.4 ARN-75039 subprotocols Exclusion criteria • History of severe gastrointestinal disease • History of chronic generalized pruritus * History of severe chronic liver disease * History of severe cardiac disorder