Study of Obeldesivir as Postexposure Prophylaxis for Filovirus Diseases Virus Disease

Key Inclusion Criteria: * Able to understand and give written informed consent and comply with treatment and follow up. * Individuals who are of childbearing potential and engage in heterosexual intercourse must agree to use protocol-specified method(s) of contraception * Known or suspected high-risk exposure to Ebola virus (EBOV), Sudan virus (SUDV), or Marburg virus (MARV) within 21 days of Day 1. High-risk exposure may include the following: 1. Direct contact with bodily fluids from a confirmed case. 2. Needle stick injury with a needle potentially contaminated with virus. 3. Prolonged exposure to an individual with EBOV, SUDV, or MARV infection or disease without (adequate) personal protective equipment. Key Exclusion Criteria: * Individuals with plans to breastfeed during the study period and 21 days following the last dose of study intervention. World Health Organization guidance on breastfeeding should be followed. * Known hypersensitivity to the study intervention, its metabolites, or formulation excipient. * Known EBOV, SUDV, or MARV reverse transcriptase-polymerase chain reaction (RT-PCR) positivity or symptomatic filovirus disease as attributed by the investigator. * Known moderate or severe renal impairment or known estimated glomerular filtration rate (eGFR) \< 60 mL/min/1.73 m\^2. * Decompensated cirrhosis (Child-Pugh Class C), acute liver injury/failure (eg, new onset \[\< 2 weeks\] of easy bruising, jaundice, ascites, hepatic encephalopathy, asterixis), and/or known alanine aminotransferase ≥5 × upper limit of normal. Note: Other protocol defined Inclusion/Exclusion criteria may apply.