Two Cases of Immune Thrombocytopenia (ITP) Related to Viral Vector Vaccination ChAdOx1-S (AstraZeneca) and a Good Response after Thrombopoietin Receptor Agonist (TPO-RA) Therapy.

Background: In 2019, a new coronavirus disease emerged in Wuhan, China, known as SARS-CoV-2, severe acute respiratory syndrome coronavirus 2, and caused an ongoing pandemic. Symptomatology of the syndrome is variable, with complications extending to hematopoiesis and hemostasis. Approximately a year after onset of the virus, four vaccination formulas became available to the public, based on a viral vector or mRNA technology. These vaccine formulas have been hampered with hematological complications, like vaccine-induced immune thrombotic thrombocytopenia (VITT) and vaccine-related ITP (immune thrombocytopenic purpura). ITP is a disease with autoimmune pathogenesis characterized by antibody production against platelets and an increased hemorrhagic risk. A decent number of cases have been referred to as possible adverse effects of COVID-19 vaccinations.

Case presentation: in this case report, we present two cases of newly diagnosed ITP after vaccination with ChAdOx1-S (AstraZeneca), with a good response to treatment with thrombopoietin-receptor agonists (TPO-RAs).

Discussion: we observed an absence of response after corticosteroids and IVIG therapy and a positive therapeutic outcome on TPO-RA.

Conclusions: in the ongoing pandemic, there is an urgent need to create therapeutic guidelines for vaccination-related clinical entities and to clarify indications for the vaccination of patients with pre-existing hematological diseases.