Type 1 diabetes mellitus following COVID‐19 RNA‐based vaccine

The epidemic of coronavirus disease‐2019 (COVID‐19) is the major public health issue in the world. COVID‐19 vaccines are one of the most effective strategies against COVID‐19. Here we report a 36‐year‐old female patient who had thirst, polydipsia, polyuria, palpitations, loss of appetite, and fatigue 3 days after the first dose of COVID‐19 RNA‐based vaccines without a prior history of diabetes. Ten days after vaccination, she visited our hospital with diabetic ketoacidosis and was diagnosed with type 1 diabetes. Hyperglycemia (501 mg/dL), anion gap metabolic acidosis and ketonuria were observed. The glycated hemoglobin level was 7.0%. Islet‐related autoantibodies were all negative. The glucagon tolerance test revealed attenuated secretion of insulin. Human leukocyte antigen was haplotype DRB1*0405‐DQB1*0401, which was associated with type 1 diabetes in Japan. The present case suggests that COVID‐19 RNA‐based vaccines might trigger the onset of type 1 diabetes, even in subjects without prior histories of diabetes.