Presentation Details
| The Prevalence of Thrombotic Events Reported Following SARS-Cov2 Vaccine Receipt: Data from The ITP Natural History Study Registry Jennifer DiRaimo1, Caroline Kruse1, Kate Foster1, Alexandra Kruse1, 2, Howard Liebman3, Craig Kessler4. 1Platelet Disorder Support Association, Cleveland, OH, USA.2Tulane University School of Medicine, New Orleans, LA, USA.3Jane Anne Nohl Division of Hematology and Center for the Study of Blood Diseases, Norris Comprehensive Cancer Center, Los Angeles, CA, USA.4Vincent Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, USA |
Abstract
Background: Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder that affects all races and ages causing a low platelet count with increased bleeding risks, and an increased risk for thrombosis. The use of thrombopoietin receptor agonists (TPO-RA) for the treatment of ITP has also been associated with a risk of thrombosis due to stimulation of platelets and other hemostatic agents. Thrombotic events have also been reported following SARS-CoV2 infection and administration of related vaccines. Objectives: We sought to understand the prevalence of thrombotic events reported in the ITP Natural History Study Registry following a COVID-19 vaccine dose. Methods: Prospective data was collected using responses from three surveys within the ITP Natural History Study Registry up to September 27, 2023. Children and adults with ITP were included upon completion of all three registry surveys. This cohort was divided into clotting and non-clotting patients and was analyzed with descriptive statistics and Fischer's exact test. Results: The study included 695 participants; 667 were adults (ages 18-87 years), and 28 were children (ages 1-17 years). 8 adults (1%) reported a thrombotic event following administration of a COVID-19 vaccine. Three participants reporting a thrombotic event disclosed the dose and vaccine manufacturer associated with the event: Pfizer vaccine (3rd dose), Moderna (2nd dose, and Pfizer (4th dose). Three of the eight participants who reported thrombosis reported having a personal history of blood clots. One participant in the clotting group reported having surgery three months before developing a thrombosis. Participants were an average age of 56 years in the clotting group (n=8) vs. 47 years in the non-clotting group (n=687). Most of the cohort was female (62% and 75%), with a primary diagnosis of ITP (87% and 99%). The clotting group mostly had a BMI greater than 35 (75%) vs. 21% in the non-clotting group. None of the clotting patients had another autoimmune disease; 9% of the non-clotting patients did, the most common being lupus. Half the clotting patients were asplenic vs. 27% of the non-clotting group. The clotting group had a higher splenectomy rate (p=0.071) and was more likely to have a BMI of 35 or greater (p=0.0325). Regarding treatment, 37% of the clotting group received a TPO-RA within the last 6 months vs. 18% in the non-clotting group. Conclusion: Thrombotic events reported following receipt of a SARS-CoV2 vaccine dose are uncommon among individuals with ITP in our registry. Some participants who reported thrombosis also had a history of thrombosis or other risk factors. Future studies should look into the impact of other vaccinations and medications (such as statins) that could be impacting thrombotic risk, not assessed in this study. Particularly, whether receiving more than one vaccine at once impacts thrombotic risk. These results should serve as an additional reassurance to the ITP community that COVID-19 vaccines are safe, and the risk for a thrombotic event is greater for ITP patients who struggle with obesity and had a splenectomy. Such individuals should be monitored more closely with newly updated vaccines as their thrombotic potential is unknown.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.