[Development of thrombocytopenic purpura following BNT162b2 mRNA COVID-19 vaccination].

Because the coronavirus disease 2019 (COVID-19) pandemic is still rampant, vaccination is being promoted worldwide. However, the safety of various COVID-19 vaccines remains poorly understood. We herein report the case of a 37-year-old woman who experienced thrombocytopenia following BNT162b2 mRNA COVID-19 vaccination. The patient presented with purpura on the extremities 10 days after the first vaccination. She had marked thrombocytopenia and no thrombosis. Thrombocytopenia resolved spontaneously. Given the possibility of occurrence of post-vaccination thrombocytopenia, vaccinated persons should be instructed to consult a medical institution if they experience bleeding symptoms.