Abstract
The vaccine for the coronavirus disease 2019 (COVID-19) has been reported to potentially cause or worsen diabetes. A 73-year-old Japanese woman received two doses of Moderna COVID-19 vaccine. Four weeks after the second vaccination, her glycemic control began to deteriorate, and 8 weeks after the second vaccination, the patient was diagnosed with new-onset type 1 diabetes that was strongly positive for autoantibodies and showed a disease-susceptible human leukocyte antigen haplotype, DRB1*04:05:01-DQB1*04:01:01. The glucagon stimulation test suggested an insulin-dependent state, and induction of intensive insulin therapy brought about fair glycemic control. The time period from the COVID-19 vaccination to the development of type 1 diabetes was relatively longer than to the onset or exacerbation of type 2 diabetes, as previously reported, suggesting the complicated immunological mechanisms for the destruction of β-cells associated with the vaccination. In recipients with the disease-susceptible haplotypes, one should be cautious about autoimmune responses for several months after the vaccination.