The incidence of type 1 diabetes has been progressively increasing during the past several decades, particularly among children younger than 5 years.1 At the same time, there has been substantial progress in understanding the pathogenesis of the disease and identifying those at risk of progressing to type 1 diabetes.2 In children at genetic risk, diabetes-related autoantibodies appear, followed by the evolution of metabolic abnormalities and the eventual clinical appearance of the disease.2 If individuals identified by genetic markers subsequently undergo seroconversion and develop 2 or more diabetes-related autoantibodies, their risk of progression to type 1 diabetes is 75% over 10 years and appears to be almost inevitable over 20 years.3 However, attempts at both primary prevention, ie, before seroconversion, and secondary prevention, ie, in those with diabetes-related autoantibodies, have not been successful.4 The interventions evaluated to date have been limited to those deemed extremely safe, because such interventions would be used in at-risk individuals who may or may not actually progress to type 1 diabetes.