Participants will be randomized to closed loop control (CLC) system (t:slim X2 with Control-IQ Technology) or to standard of care where the children will continue to use his or her personal insulin pump or multiple daily injections. Both groups will use a continuous glucose monitor (CGM) throughout the study. The study system will also use a study insulin pump and a software algorithm to automatically give insulin and control blood glucose. This system is also sometimes called a closed-loop system.~This study will take about 6-7 months for the child to complete. Study visits can be completed from home via videoconference (e.g. Zoom) without visiting the clinic or in-person at the clinic.~A subset of participants will be asked to join an ancillary study with Meal Bolus and Exercise challenges during the extension phase. Data collected from the start of each of these challenges until the following morning will be excluded from the analysis of the extension phase.
The purpose of this study is to learn whether an investigational automated insulin delivery system (study system) for young children (2 yo to less than 6 yo) with type 1 diabetes can safely improve blood glucose (sometimes called blood sugar) control.