IMPORTANCEThere is no specific antiviral therapy recommended for coronavirus disease 2019 . In vitro studies indicate that the antiviral effect of chloroquine diphosphate (CQ) requires a high concentration of the drug. OBJECTIVE To evaluate the safety and efficacy of 2 CQ dosages in patients with severe COVID-19. DESIGN, SETTING, AND PARTICIPANTSThis parallel, double-masked, randomized, phase IIb clinical trial with 81 adult patients who were hospitalized with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was conducted from March 23 to April 5, 2020, at a tertiary care facility in Manaus, Brazilian Amazon. INTERVENTIONS Patients were allocated to receive high-dosage CQ (ie, 600 mg CQ twice daily for 10 days) or low-dosage CQ (ie, 450 mg twice daily on day 1 and once daily for 4 days). MAIN OUTCOMES AND MEASURES Primary outcome was reduction in lethality by at least 50% in the high-dosage group compared with the low-dosage group. Data presented here refer primarily to safety and lethality outcomes during treatment on day 13. Secondary end points included participant clinical status, laboratory examinations, and electrocardiogram results. Outcomes will be presented to day 28. Viral respiratory secretion RNA detection was performed on days 0 and 4. RESULTS Out of a predefined sample size of 440 patients, 81 were enrolled (41 [50.6%] to highdosage group and 40 [49.4%] to low-dosage group). Enrolled patients had a mean (SD) age of 51.1 (13.9) years, and most (60 [75.3%]) were men. Older age (mean [SD] age, 54.7 [13.7] years vs 47.4 [13.3] years) and more heart disease (5 of 28 [17.9%] vs 0) were seen in the high-dose group. Viral RNA was detected in 31 of 40 (77.5%) and 31 of 41 (75.6%) patients in the low-dosage and highdosage groups, respectively. Lethality until day 13 was 39.0% in the high-dosage group (16 of 41) and 15.0% in the low-dosage group (6 of 40). The high-dosage group presented more instance of QTc interval greater than 500 milliseconds (7 of 37 [18.9%]) compared with the low-dosage group (4 of 36 [11.1%]). Respiratory secretion at day 4 was negative in only 6 of 27 patients (22.2%). CONCLUSIONS AND RELEVANCEThe preliminary findings of this study suggest that the higher CQ dosage should not be recommended for critically ill patients with COVID-19 because of its potential (continued) Key Points Question How safe and effective are 2 different regimens of chloroquine diphosphate in the treatment of severe coronavirus disease 2019 (COVID-19)? Findings In this phase IIb randomized clinical trial of 81 patients with COVID-19, an unplanned interim analysis recommended by an independent data safety and monitoring board found that a higher dosage of chloroquine diphosphate for 10 days was associated with more toxic effects and lethality, particularly affecting QTc interval prolongation. The limited sample size did not allow the study to show any benefit overall regarding treatment efficacy. Meaning The preliminary findings from the CloroCovid-19 trial suggest that higher dosage of chloro...

robust clinical studies on the safety and/or efficacy of chloroquine (CQ) and/or hydroxychloroquine (HCQ) for the treatment of COVID-19 during the recent 2020 pandemic.We searched PubMed and also MedRxiv.org (pre-print server for health sciences, without peer review), without any language restrictions and including Chinese publications, for studies published between Dec 2019 and April 5, 2020, using the search terms 'COVID-19, coronavirus, SARS-Cov-2'. We found three non-randomized studies with limited sample sizes in which (1) HCQ use led to a decrease in SARS-Cov-2 detected in respiratory secretions five days after treatment, together with azithromycin (France, 36 patients); (2) HCQ use shortened time to clinical recovery (China, 62 patients); and (3) CQ was superior to control treatment in inhibiting the exacerbation of pneumonia, improving lung imaging findings, and promoting virus-negative conversion and shortening the disease course (China, 100 patients). We found no published studies comparing different dosages of CQ/HCQ and their thorough safety assessment. Added value of this studyIn a larger patient population, we found that a higher dosage of CQ for 10 days presented toxicity red flags, particularly affecting QTc prolongation. The limited sample size recruited so far does not allow to show any benefit regarding treatment efficacy, however the higher fatality associated with the higher dosage by day 13 of follow-up resulted in a premature halting of this arm. This is the first double-blinded, randomized clinical trial addressing different dosages of CQ for the treatment of severe patients with COVID-19 in the absence of a control group using placebo. Due to the impossibility of not using the drug recommended at the national level, we used historical data from the literature to infer comparisons for lethality endpoints. Follow-up until day 28 is ongoing with a larger sample size, in which long-term lethality will be better estimated.

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A description of the epidemiological profile of visceral leishmaniasis among Indians in the State of Roraima, Brazil, was based on the clinical characteristics of human and dog disease, ecological aspects of the area where the cases occurred and entomologic investigations performed from 1989 to 1993. The 82 human cases were reported in six out of eight Counties that existed then in the state; there was a 69.5% predominance of male cases among those registered and a greater (52.4%) occurrence of the disease in children from zero to ten years old. The rate of natural infection was 10.3% out of 3,773 dogs examined in 74 different locations. Lutzomyia longipalpis was found in 31 areas with greater prevalence of the disease. The human and animal cases as well as the vectors were concentrated in areas where mountains and arable soil predominate, typical locations for the occurrence of American visceral leishmaniasis.