evidence: These findings suggestive of possible benefit, along with the desperation of clinicians who were providing care for patients with a potentially fatal disorder for which there was no treatment, undoubtedly contributed to increased use of hydroxychloroquine for patients with COVID-19, despite lack of rigorous evidence for efficacy. [...] These events sparked an avalanche of studies, many of which are now completed and are being reported in the scientific literature. These well-conducted trials, including the study reported in this issue of JAMA, demonstrate the lack of efficacy of hydroxychloroquine in patients with COVID-19. In a twist of irony, the US president did not receive hydroxychloroquine, with or without azithromycin, when he contracted COVID-19 and was hospitalized at Walter Reed National Military Medical Center in early October.9 Several lessons are gleaned from the experience with hydroxychloroquine in the treatment of COVID-19. First, a single report based on a small, nonrandomized study must be considered preliminary and hypothesis generating, not clinically actionable. Likewise, anecdotal case reports and case series that include several cases likewise must be considered anecdotal and preliminary. Second, US health officials, such as members of the Coronavirus Task Force, leaders from the National Institutes of Health, and officers of physician organizations and societies, who resisted being forced to promote the politically motivated use of hydroxychloroquine were correct and should be recognized for their steadfast commitment to science. Third, patients who have a potentially life-threatening disease are desperate and will accept any treatment that appears to be effective, especially when such treatment is promoted by individuals who ordinarily should be trusted, such as the US president.