Severe case of refractory immune thrombocytopenic purpura requiring splenectomy after the COVID-19 vaccine.

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder caused by autoantibodies against platelet antigens resulting in platelet destruction and inhibition of platelet production. Occasionally, an inciting event such as a virus or vaccination can precipitate ITP. Several cases of ITP have been reported after the BTN162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) SARS-CoV-2 (COVID-19) vaccines. All reported cases of post-vaccination ITP have resolved with medical therapy until this case.A man in his mid-20s developed bleeding from ITP 2 weeks after receiving the second dose of the Pfizer SARS-CoV-2 vaccine. All inpatient medical treatment attempts failed. On hospital day 40, a splenectomy was performed and he ultimately recovered and was discharged.Awareness of potential vaccination side effects is a fundamental element of refining and improving patient safety. This case illustrates that given the right circumstances, serious refractory ITP can develop in response to the second dose of the Pfizer SARS-CoV-2 vaccine.