Abstract: 2 a double-blind randomized, placebo-controlled, phase 2 trial 3 Marisa Holubar MD,1 Aruna Subramanian MD,1 Natasha Purington PhD,2 Haley Hedlin PhD,2 4 Bryan Bunning MS,2 Katharine S. Walter PhD,1 Hector Bonilla MD,1 Athanasia Boumis,3 5 Michael Chen MD,4 Kimberly Clinton,3 Liisa Dewhurst,3 Carol Epstein MD,5 Prasanna 6 Jagannathan MD,1,6 Richard H. Kaszynski MD,4 Lori Panu,3 Julie Parsonnet MD,1,7 Elizabeth L. 7 Ponder PhD,8 Orlando Quintero MD,1 Elizabeth Sefton PhD,8 Upinder Singh MD,1,6 Luke 8 Soberanis,3 Henry Truong PharmD,9 Jason R. Andrews MD,1 Manisha Desai PhD,2 Chaitan 9 Khosla PhD,10,8 Yvonne Maldonado MD11,7 10 1. 2. 13 N M Medicine, Stanford, CA, USA Quantitative Sciences Unit, Division of Biomedical Informatics Research, Department of D 12 Division of Infectious Diseases and Geographic Medicine, Stanford University School of A 11 U SC RI PT Favipiravir for treatment of outpatients with asymptomatic or uncomplicated COVID-19: Medicine, Stanford University, Palo Alto, CA, USA 3. Stanford Center for Clinical Research, Stanford University, Stanford, CA, USA 15 4. Stanford Solutions, Stanford University School of Medicine, Stanford, CA 94305, USA 16 5. Carol L. Epstein MD Consulting LLC, Wellington, FL, USA 17 6. Department of Microbiology and Immunology, Stanford University School of Medicine, 7. 20 21 EP Stanford, CA, USA A 19 CC 18 TE 14 8. Department of Epidemiology and Population Health, Stanford University School of Medicine, Stanford, CA, USA Stanford ChEM-H, Stanford University, Stanford CA, USA © The Author(s) 2022. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons AttributionNonCommercial-NoDerivs licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits noncommercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com 1 1 1 9. Mariner Advanced Pharmacy Corp, San Mateo, California 2 10. Departments of Chemistry and Chemical Engineering, Stanford University, Stanford, 3 CA, USA 4 11. 5 Correspondence: 6 Marisa Holubar, MD MS 7 Clinical Associate Professor of Medicine 8 Division of Infectious Diseases and Geographic Medicine 9 Stanford University School of Medicine 10 300 Pasteur Drive, Lane Building 145 Stanford, CA 94305 USA 11 mholubar@stanford.edu U N A M D TE EP CC A 12 SC RI PT Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA 2 Background: Favipiravir is an oral, RNA-dependent RNA polymerase inhibitor with in vitro 3 activity against SARS-CoV2. Despite limited data, favipiravir is administered to patients with 4 COVID-19 in several countries. 5 Methods: We conducted a phase 2 double-blind randomized controlled outpatient trial of 6 favipiravir in asymptomatic or mildly symptomatic adults with a positive SARS-CoV2 RT-PCR 7 within 72 hours of enrollment. Participants were randomized 1:1 to receive placebo or favipiravir 8 (1800..