Abstract: medRxiv preprint doi: https://doi.org/10.1101/2021.02.01.21250371; this version posted February 5, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . HCQ for severe COVID-19 HYDROXYCHLOROQUINE FOR THE TREATMENT OF SEVERE RESPIRATORY INFECTION BY COVID-19: A RANDOMIZED CONTROLLED TRIAL AUTHORS: Carmen Hernandez-Cardenas1, Ireri Thirion-Romero1, Norma E. RiveraMartinez2, Patricia Meza-Meneses3, Arantxa Remigio-Luna1, Rogelio Perez-Padilla1 on behalf of the Research Group on hydroxychloroquine for COVID-19 * *The research group also formed by Drs. Luis Felipe Jurado-Camacho1, Sebastián RodríguezLlamazares1, Teresa Aguirre-Pérez1, Joel Armando Vásquez-Pérez1, and Alejandra RamirezVenegas1, from the Instituto Nacional de Enfermedades Respiratorias Mexico City, and Drs. Gabriela Tapia-Pastrana2, Nestor G. Cruz-Ruiz2 from the Hospital de Referencia de Alta Especialidad Oaxaca. 1- Instituto Nacional de Enfermedades Respiratorias; CP 14080, Mexico City, Mexico. 2- Hospital Regional de Alta Especialidad Oaxaca; CP 71256, Oaxaca, Mexico. 3-Hospital Regional de Alta Especialidad Ixtapaluca; CP 53560, Edo de México, Mexico. Correspondence: Dr. Rogelio Perez Padilla, Instituto Nacional de Enfermedades Respiratorias, Mexico City. e-mail perezpad@gmail.com 1 NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. medRxiv preprint doi: https://doi.org/10.1101/2021.02.01.21250371; this version posted February 5, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC-ND 4.0 International license . HCQ for severe COVID-19 ABSTRACT The novel coronavirus pandemic (COVID–19) represents a major public health problem due to its rapid spread and its ability to generate severe pneumonia. Thus, it is essential to find a treatment that reduces mortality. Our objective was to estimate whether treatment with 400 mg/day of Hydroxychloroquine for 10 days reduces in-hospital mortality in subjects with severe respiratory disease due to COVID-19 compared with placebo. Material and methods: A double-blind, randomized, placebo-controlled trial to evaluate the safety and efficacy of Hydroxychloroquine for the treatment of severe disease by COVID-19 through an intention-to-treat analysis. Eligible for the study were adults aged more than 18 years with COVID-19 confirmed by RT-PCR and lung injury requiring hospitalization with or without mechanical ventilation. Primary outcome was 30-day mortality. Secondary outcomes: days of mechanical ventilation, days of hospitalization and cumulative incidence of serious adverse events. Results: A total of 214 patients with COVID-19 were recruited, randomized and analyzed. They were hypoxemic with a mean SpO2 of 65% ± 20, tachycardic (pulse rate 108±17 min-1) and tachypneic (32 ±10 min-1); 162 were under mechanical ventilation at randomization. Thirty-day mortality was similar in both groups (38% in Hydroxychloroquine vs. 41% in placebo, hazard ratio [HR] 0.88, 95% Confidence Interval [95%CI] 0.51-1.53). In the surviving participants, no significant difference was found in secondary..