On April 3, 2020, data were published showing in vitro efficacy of ivermectin against COVID-19. By April 26, 2020, Schmith et al. published that even at supratherapeutic doses, ivermectin was unlikely to reach target IC90 concentrations in vivo. Nevertheless, many countries adopted ivermectin, and millions of patients received treatment even after definitive evidence of ineffectiveness became available. The ivermectin debate catalyzed public mistrust in science and health authorities and has consequences for future pandemic preparedness.