To the Editor We read with great interest the publications by Bessière et al1 and Mercuro et al2 regarding the QT prolongation in patients with coronavirus disease 2019 (COVID-19)–related pneumonia treated with hydroxychloroquine. Both the studies raised safety concern about hydroxychloroquine usage secondary to a higher than expected QT prolongation connected to the treatment. In particular, 18 of 90 patients (20%) in the study by Mercuro et al2 and 7 of 40 patients (18%) in the study by Bessière et al1 developed a corrected QT interval greater than 500 ms. Moreover, coadministration with azithromycin worsened the risk of QT prolongation, and 1 patient in the study by Mercuro et al2 developed torsades de pointes 3 days after medications withdrawal.