This study is testing a medication, called hydroxychloroquine (HCQ) to assess safety and effectiveness to prevent individuals at risk of type 1 diabetes (T1D) from progressing to type 1 diabetes. HCQ is approved by the U.S. Food and Drug Administration as a treatment for malaria, lupus, and rheumatoid arthritis. HCQ has been used extensively for treatment of autoimmune disease in adults, children, and during pregnancy. This medication has not previously been studied as a treatment to prevent T1D. The goal of this study is to learn if HCQ can help prevent or delay progression from normal glucose tolerance (Stage 1) to abnormal glucose tolerance (Stage 2) or type 1 diabetes (Stage 3). The study involves 5 visits in the first 6 months, then 1 visit every 6 months for the remainder of the study.