The incidence of type 1 diabetes is increasing, especially in young children. Early diagnosis is possible in the asymptomatic stage of islet autoimmunity. Screening is offered to high-risk families, but also feasible and useful in the general population, in studies such as Fr1da(plus)in Bavaria (Germany). Complications at clinical manifestation can be prevented by early diagnosis. Participation in experimental interventions to delay stage progression is possible. Numerous approaches to secondary prevention are being pursued. Treatment with the monoclonal antibody teplizumab successfully delayed progression to clinical diabetes in patients in stage 2. Infants at high risk for developing type 1 diabetes can be identified by genetic screening. Primary prevention pursues, among others, the goal of preventing the onset of the autoimmune reaction. The POInT trial aims to improve immune tolerance to insulin by oral exposure in high-risk children and to delay or prevent the onset of autoimmunity. Following up on the focus issue "Early detection and preventive treatment of type 1 diabetes" published in this journal in 2018, this article gives an update on selected developments over the past 2 years.