Abstract: ORIGINAL RESEARCHES Ram Niwas 1, Aneesa Shahul S 1, M K Garg 2, Vijaya Lakshmi Nag 3, Pradeep Kumar Bhatia 4, Naveen Dutt 1, Nishant Chauhan 1, Jaykaran Charan 5, Shahir Asfahan 1, Praveen Sharma 6, Pankaj Bhardwaj 7, Mithu Banerjee 6, Pawan Garg 8, Binit Sureka 8, Gopal Krishna Bohra 2, Maya Gopalakrishnan 2, Sanjeev Misra 9 1 Department of Pulmonary Medicine, All India Institute of Medical Sciences Jodhpur, India Department of General Medicine, All India Institute of Medical Sciences Jodhpur, India 3 Department of Microbiology, All India Institute of Medical Sciences Jodhpur, India 4 Department of Anaesthesiology & Critical Care, All India Institute of Medical Sciences Jodhpur, India 5 Department of Pharmacology, All India Institute of Medical Sciences Jodhpur, India 6 Department of Biochemistry, All India Institute of Medical Sciences Jodhpur, India 7 Department of Community Medicine and Family Medicine, All India Institute of Medical Sciences Jodhpur, India 8 Department of Diagnostic & Interventional Radiology, All India Institute of Medical Sciences Jodhpur, India 9 Department of Surgical Oncology, All India Institute of Medical Sciences Jodhpur, India 2 Clinical outcome, viral response and safety profile of chloroquine in COVID-19 patients — initial experience Abstract Introduction: Chloroquine and its analogues are currently being investigated for the treatment and post exposure prophylaxis of COVID-19 due to its antiviral activity and immunomodulatory activity. Material and methods: Confirmed symptomatic cases of COVID-19 were included in the study. Patients were supposed to receive chloroquine (CQ) 500 mg twice daily for 7 days. Due to a change in institutional protocol, initial patients received chloroquine and subsequent patients who did not receive chloroquine served as negative controls. Clinical effectiveness was determined in terms of timing of symptom resolution and conversion rate of reverse transcriptase polymerase chain reaction (RT-PCR) on day 14 and day 15 of admission. Results: Twelve COVID-19 patients formed the treatment arm and 17 patients were included in the control arm. The duration of symptoms among the CQ treated group (6.3 ± 2.7 days) was significantly (p-value = 0.009) lower than that of the control group (8.9 ± 2.2 days). There was no significant difference in the rate of RT-PCR negativity in both groups. 2 patients out of 12 developed diarrhea in the CQ therapy arm. Conclusion: The duration of symptoms among the treated group (with chloroquine) was significantly lower than that of the control group. RT-PCR conversion was not significantly different between the 2 groups. Key words: COVID-19, chloroquine, viral conversion, safety profile Adv Respir Med. 2020; 88: 515–519