Coronavirus disease 2019 (COVID-19) has emerged as a global pandemic until today, but treatment options remain limited. COVID-19 vaccination is expected to decrease the number of patients with COVID-19 worldwide. In Japan, two types of mRNA COVID-19 vaccine, BNT162b2 (Pfizer/BioNTech) and mRNA-1273 (Moderna), have been approved and administered. However, their side effects remain poorly elucidated. This paper presents two cases of immune thrombocytopenia (ITP) after BNT162b2 mRNA COVID-19 vaccination. Whether or not ITP is triggered by the vaccination or not is difficult to identify. Further investigation with a large number of cases is warranted to clarify the side effects of BNT162b2 mRNA COVID-19 vaccination.
Keywords: COVID-19; Immune thrombocytopenia; SARS-CoV-2 vaccine.