Hemophagocytic Lymphohistiocytosis after Vaccination
An 85-year-old Japanese woman with chronic renal failure and hypertension developed malaise, vomiting, and persistent high fever (up to 39.7°C) on the 12th day after receiving the second dose of the BNT162b2 vaccine. Initial evaluation revealed neutropenia. Further tests showed hyperferritinemia (serum ferritin 2284.4 μg/L). Bone marrow examination revealed haemophagocytosis. A provisional diagnosis of HLH associated with the Comirnaty® vaccination was made based on the HLH-2004 diagnostic criteria.