Rapid and severe worsening of diabetes in a heart transplant recipient after Johnson and Johnsons Janssen COVID-19 vaccine administration

The COVID-19 vaccines are usually safe, effective, and well-tolerated by the general population. After the COVID-19 vaccines are widely used, rare and potentially severe vaccine complications become more manifest. Here reported is a case of rapid and severe worsening of diabetes after the Johnson & Johnson's Janssen COVID-19 vaccine (J&J COVID vaccine) administration. A 55-year-old male heart transplant recipient with metformin (500 mg twice daily)-controlled mild diabetes started to have flu-like symptoms a few days after receiving the J&J COVID vaccine. His fasting glucose levels had ranged between 130-150 mg/dL (normal 65-99) before he received the J&J COVID vaccine. The fasting glucose rose to ~200 mg/dL one day after the vaccine administration and gradually rose to ~400 mg/dL over the next few weeks. He presented to the endocrine clinic urgently. Point-of-care fasting glucose was 382 mg/dL and A1c 13.0 (which was 6.7 six months before). Bicarbonate and anion gap were normal, insulin and C-peptide in the low normal range, and β cell autoantibodies negative. Multi-dosing insulin treatment was immediately started and the doses titrated up to insulin glargine 30 units daily and insulin lispro 10 units before each meal. He improved clinically with well-controlled glycemia. The rapid and severe worsening of his diabetes after the vaccination suggests that the J&J COVID vaccine could severely deteriorate diabetes control in some patient populations.