[Autoimmune hemolytic anemia following the third dose of the COVID-19 vaccine].

The development and exacerbation of autoimmune diseases following coronavirus disease 2019 (COVID-19) vaccination have been reported; however, there are few reports of autoimmune hemolytic anemia (AIHA). A 75-year-old woman was admitted to the emergency department 46 days after receiving her third dose of the mRNA-1273 COVID-19 vaccine because of fatigue and general weakness. Initial laboratory analyses revealed severe hemolytic anemia with positive direct and indirect Coombs test and elevation of serum indirect bilirubin and lactate dehydrogenase. The patient had no underlying disease after a close examination and was diagnosed with warm AIHA, which was thought to be associated with COVID-19 vaccination. The anemia improved daily after the administration of prednisolone. Clinicians should be aware of the possibility of AIHA being caused by COVID-19 vaccination, and monotherapy with prednisolone should be considered in cases of severe anemia.