Abstract
Primary immune thrombocytopenia (ITP) is an acquired autoimmune disease with highly variable presentation, characteristics, and clinical course. Thrombocytopenia is a common complication of many viral infections, including SARS-CoV-2. In addition, both de novo ITP and exacerbation of ITP after vaccination against SARS-CoV-2 have been reported. Patients infected with SARS-CoV-2 develop a prothrombotic coagulopathy called COVID-19-associated coagulopathy (CAC). In addition, autoimmune hematological disorders secondary to SARS-CoV-2 infection, mainly ITP and autoimmune hemolytic anemia (AIHA), have been described. Furthermore, SARS-CoV-2 infection has been associated with exacerbation of autoimmune processes, including ITP. In fact, there is evidence of a high relapse rate in patients with preexisting ITP and COVID-19. As for vaccination against SARS-CoV-2, hematological adverse events (HAE) are practically anecdotal. The most common HAE is thrombocytopenia-associated thrombosis syndrome (TTS) linked to vectored virus vaccines. Other HAEs are very rare, but should be considered in patients with previous complement activation disease or autoimmunity. In patients with ITP who are vaccinated against SARS-CoV-2, the main complication is exacerbation of ITP and the bleeding that may result. In fact, this complication occurs in 12% of patients, with splenectomized and refractory patients with more than five lines of previous treatment and platelet counts below 50 × 10(9)/L being the most vulnerable. We conclude that, in general, there is no greater risk of severe SARS-CoV-2 infection in ITP patients than in the general population. Furthermore, no changes are advised in patients with stable ITP, the use of immunosuppressants is discouraged unless there is no other therapeutic option, and patients with ITP are not contraindicated for vaccination against COVID-19.