LAssa Fever Adjunct Treatment With DEXamethasone

Inclusion Criteria: * Age ≥ 18 years * LF confirmed by RT-PCR (reverse-transcription polymerase chain reaction) with a cycle threshold (Ct) value \< 30 * Signs of significant health impairment as evidenced by any of the following: * Alert, confusion, voice, pain, unresponsive (ACVPU) other than A * Systolic blood pressure \< 90 mmHg * Seizure(s), meningism, coma, focal neurological deficit * AST (GOT) \>3xULN * ALT (GPT) \> 3xULN * KDIGO 2 or more severe based on serum creatinine only * Active macroscopic bleeding * O2 saturation \< 92 Exclusion Criteria: * Pregnancy (evidenced by positive urine pregnancy test in women of child-bearing potential) * Lactation following live birth * Known intolerance and contra-indications to ribavirin or dexamethasone * Patients who already received a corticosteroid within the preceding 7 days * Investigator's valuation that patient might be put to substantial risk by participating in this trial * Patients receiving end-of-life care as judged by the investigator