Inclusion Criteria:  Adults (greater than or equal to [>=] 18 years) with SARS-CoV-2 infection. Participants with symptoms and/or signs consistent with COVID-19, requiring treatment. A score of Grade 3 to 5 on the 9-point ordinal scale. In India; only Participants with a score of Grade 4 or 5 will be enrolled. a) Male Participants:  A male Participant must agree to use contraception during the treatment period and for at least 120 days after the last dose of study treatment and refrain from donating sperm during this period.  b) Female Participants:  A female Participant is eligible to participate if she is not pregnant, not breastfeeding, and at least 1 of the following conditions applies:  Not a woman of childbearing potential. OR A woman of childbearing potential who agrees to follow the contraceptive guidance during the treatment period and for at least 120 days after the last dose of study treatment. Women who are lactating who agree not to breastfeed their child during the study and for at least 120 days after termination of study therapy (they may continue to express milk away from the child during this period, but this milk must be discarded). Ability to provide informed consent signed by the study Participant or legally authorized representative.  Exclusion Criteria:  Participants who have previously had a score of 6 or 7 on the 9-point ordinal scale. Inability to swallow capsules (administration via nasogastric tube is permitted in Participants who become unable to swallow after starting the study drug).  History of the following cardiac conditions:  Myocardial infarction within 3 months prior to the first dose Unstable angina History of clinically significant dysrhythmias (long QT features on electrocardiogram [ECG], sustained bradycardia [less than or equal to {<=} 55 beats per minute {bpm}]), left bundle branch block, or ventricular arrhythmia) or history of familial long QT. Participants with an implantable cardioverter defibrillator device in place, will be allowed to enroll. Atrial fibrillation will not be a reason for exclusion. Screening 12-lead ECG with a measurable QT interval according to Fridericia correction (QTcF) greater than (>) 470 msec. Clinically significant hypokalaemia. Therapeutic anticoagulation with vitamin K antagonists. Previous bowel resection that would interfere with drug absorption. Any participant whose interests are not best served by study participation, as determined by a senior attending clinician. Alanine aminotransferase/aspartate aminotransferase >5 × the upper limit of normal. Current treatment for human immunodeficiency virus (HIV) or tuberculosis (TB). Positive serologic assay at screening for hepatitis B virus (Hep B surface antigen) or hepatitis C virus (hepatitis C PCR or hepatitis C core antigen) at local laboratory. Stage 4 severe chronic kidney disease. Anticipated transfer to another hospital that is not a study center within 72 hours. Allergy to any study treatment. Experimental off-label usage of medicinal products as treatments for COVID-19 at the time of enrolment. Participants participating in another clinical study of an investigational medicinal product. Current or planned treatment for TB.