New-Onset Type 1 Diabetes Mellitus Following Hepatitis B Vaccination: Case Report and Review of Vaccine-Induced Autoimmune Mechanisms

Abstract

While vaccinations are critical for preventing viral infections, several reports have documented autoimmune conditions following immunization. We present a case of new-onset type 1 diabetes mellitus (T1DM) that occurred after Hepatitis B vaccination. A 42-year-old African American woman presented with polyuria, polydipsia, and unintended weight loss two months after receiving a Hepatitis B vaccine. Initial laboratory analysis showed a hemoglobin A1c (HbA1c) of 9.8%, along with elevated titers of anti-glutamic acid decarboxylase (GAD-65) antibodies. The patient was initiated on insulin therapy and remains under glycemic control. Potential mechanisms for T1DM post-vaccination include autoimmune activation triggered by molecular mimicry and inflammatory responses. Though rare, this case underscores the importance of timely screening for hyperglycemia in patients with new-onset symptoms following vaccination. This case highlights the need for awareness of immune-related adverse events following vaccinations. Early recognition and management are key to minimizing long-term complications.