Cases of de novo
immune thrombocytopenia (
ITP), including a fatality, following SARS-CoV-2 vaccination in previously healthy recipients led to studying its impact in preexisting
ITP. In this study, 4 data sources were analyzed: the
Vaccine Adverse Events Reporting System (VAERS) for cases of de novo
ITP; a 10-center retrospective study of adults with preexisting
ITP receiving SARS-CoV-2 vaccination; and surveys distributed by the Platelet Disorder Support Association (PDSA) and the United Kingdom (UK)
ITP Support Association. Seventy-seven de novo
ITP cases were identified in VAERS, presenting with median platelet count of 3 [1-9] ×109/L approximately 1 week postvaccination. Of 28 patients with available data, 26 responded to treatment with
corticosteroids and/or
intravenous immunoglobulin (
IVIG), and/or
platelet transfusions. Among 117 patients with preexisting
ITP who received a
SARS-CoV-2 vaccine, 19 experienced an
ITP exacerbation (any of: ≥50% decline in platelet count, nadir platelet count <30 × 109/L with >20% decrease from baseline, and/or use of rescue
therapy) following the first dose and 14 of 70 after a second dose. Splenectomized persons and those who received 5 or more prior lines of
therapy were at highest risk of
ITP exacerbation. Fifteen patients received and responded to rescue treatment. In surveys of both 57 PDSA and 43 UK patients with
ITP, prior
splenectomy was associated with worsened
thrombocytopenia.
ITP may worsen in preexisting
ITP or be identified de novo post-SARS-CoV2 vaccination; both situations responded well to treatment. Proactive monitoring of patients with known
ITP, especially those postsplenectomy and with more refractory disease, is indicated.