Progression of hemolysis in a patient with hereditary spherocytosis after the second dose of COVID-19 mRNA vaccine.

Herein, we report the case of a 22-year-old woman with hereditary spherocytosis (HS) whose condition worsened after administration of the coronavirus disease 2019 (COVID-19), mRNA vaccine 'BNT162b2 Pfizer-BioNTech.' The woman had been diagnosed with HS in 2005, and her condition remained stable until February 2021. In March 2021, she received the first dose of the above vaccine and experienced pain at the injection site. After the second dose in April 2021, she developed fever and general malaise. Investigations revealed progression of hemolysis, which improved after a few days. To the best of our knowledge, this is the first report of progression of hemolysis in a patient with HS after administration of the mRNA vaccine COVID-19, BNT162b2 'Pfizer-BioNTech.'