New Onset of Type 1 Diabetes Mellitus Post-COVID-19 Vaccine.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with an increased morbidity and mortality worldwide. Coronavirus disease 2019 (COVID-19) vaccines have shown high efficacy in preventing the infection but with many possible side effects such as hyperglycemia. New-onset diabetes mellitus (DM) and severe metabolic complications have been reported post-vaccination. Here we report a 45-year-old woman who came to the hospital complaining of polyurea, polydipsia, and weight loss 3 weeks after the first activation dose of COVID-19 vaccine. Her hemoglobin A1c (HbA1c) upon presentation was 9% without any prior history of DM. She was diagnosed with type 1 diabetes mellitus (T1DM), as the anti-glutamic acid decarboxylase (GAD) antibody was positive and complicated during follow-up with diabetic ketoacidosis (DKA). This is the first case in Saudi Arabia suggesting that the COVID-19 RNA-based vaccines might cause new onset of T1DM, complicated by late DKA.