Abstract: medRxiv preprint doi: https://doi.org/10.1101/2020.03.22.20040758; this version posted April 10, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.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 . Efficacy of hydroxychloroquine in patients with COVID-19: results of a randomized clinical trial Zhaowei Chen1, , Jijia Hu1, , Zongwei Zhang1, Shan Jiang2, Shoumeng Han3, Dandan Yan4, Ruhong Zhuang5, Ben Hu 6 and Zhan Zhang7,* 1 Department of Nephrology, Renmin Hospital of Wuhan University, Wuhan 430060, China. 2 Department of Dermatology, Renmin Hospital of Wuhan University, Wuhan 430060, China. 3 Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan 430060, China. 4 Department of Pathology, Renmin Hospital of Wuhan University, Wuhan 430060, China. 5 Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China. 6 CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430060, China. 7 Department II of Respiratory Disease and Intensive Care, Renmin Hospital of Wuhan University, Wuhan 430060, China. Zhaowei Chen and Jijia Hu contributed equally to this work. * Corresponding author: Zhan Zhang, Department II of Respiratory Disease and Intensive Care, Renmin Hospital of Wuhan University, Wuhan 430060, China. Email: doctorzhang2003@163.com Abstract Aims: Studies have indicated that chloroquine (CQ) shows antagonism against COVID-19 in vitro. However, evidence regarding its effects in patients is limited. This study aims to evaluate the efficacy of hydroxychloroquine (HCQ) in the treatment of patients with COVID-19. Main methods: From February 4 to February 28, 2020, 62 patients suffering from COVID-19 were diagnosed and admitted to Renmin Hospital of Wuhan University. All participants were randomized in a parallel-group trial, 31 patients were assigned to receive an additional 5-day HCQ (400 mg/d) treatment, Time to clinical recovery (TTCR), clinical characteristics, and radiological results were assessed at baseline and 5 days after treatment to evaluate the effect of HCQ. Key findings: For the 62 COVID-19 patients, 46.8% (29 of 62) were male and 53.2% (33 of 62) were female, the mean age was 44.7 (15.3) years. No difference in the age and sex distribution between the control group and the HCQ group. But for TTCR, the body temperature recovery time and the cough 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/10.1101/2020.03.22.20040758; this version posted April 10, 2020. 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 . remission time were significantly shortened in the HCQ treatment group. Besides, a larger proportion of patients with improved pneumonia in the HCQ treatment group (80.6%, 25 of 31) compared with the control group (54.8%, 17 of 31). Notably, all 4 patients progressed to severe illness that occurred in the control group. However, there were 2 patients with mild adverse reactions in the HCQ treatment group. Significance: Among..