Klein NP, et al. - In this retrospective cohort study, researchers ascertained if human papillomavirus (HPV) vaccine is associated with a long-term increased risk of diabetes mellitus type 1 (DM1). They studied all potential cases of DM1 that were identified from members of Kaiser Permanente Northern California (KPNC) aged 11-26 years at any time from June 2006 to December 2015. The analysis of DM1 included 911,648 people. No increased risk was found for the development of DM1 following HPV vaccination.