Exacerbation of immune thrombocytopenia following COVID-19 vaccination.

There is concern that COVID-19 vaccination may adversely affect immune thrombocytopenia (ITP) patients. Fifty-two consecutive chronic ITP patients were prospectively followed after COVID-19 vaccination. Fifteen percent had no worsening of clinical symptoms but no post-vaccination platelet count; 73% had no new symptoms and no significant platelet count decline. However, 12% had a median platelet count drop of 96% within 2-5 days post vaccination with new bleeding symptoms; after rescue therapy with corticosteroids +/- intravenous immunoglobulin (IVIG), platelets recovered to >30 × 109 /l a median three days later. ITP exacerbation occurred independently of remission status, concurrent ITP treatment, or vaccine type. Safety of a second vaccine dose needs careful assessment.