Immune Thrombocytopenia Purpura Relapse in Patients Who Received mRNA COVID-19 Vaccines

Abstract

Background: Immune thrombocytopenic purpura (ITP) is a syndrome in which platelets become coated with autoantibodies to platelet membrane antigens. The mononuclear macrophage system of the spleen is responsible for removing platelets in ITP. This leads to a decrease in circulating platelet count and propensity for bleeding. Patients usually present with bruising and mucosal bleeding, with a minority of cases developing major bleeding complications such as intracranial hemorrhage. Cases of ITP and ITP relapse have been reported in people who received the mRNA SARS-CoV-2 vaccine, most reported cases present with bruising and mucosal bleeding in the first few weeks after receiving the vaccine, nevertheless, the causal relationship is not yet proved. Objectives: This study aims to prove the causal relationship betweenITP relapse in known ITP patients and the mRNA covid vaccine. And to evaluate the long-term effect of the vaccine on ITP patients > 6 months after receiving the second dose. Methods a retrospective study was conducted to check platelet count in 67 patients known for immune thrombocytopenia purpura, who are >18-year- old, and not known for any other causes of thrombocytopenia (including congenital thrombocytopenia, malignancy, SLE, anti-phospholipid syndrome). The platelet count was identified at baseline before receiving the vaccine and within 3 months, 6 months, and after 6 months after receiving the vaccine. Results: The results showed that 6% of ITP patients had ITP relapse within the first 3 months after the mRNA covid vaccine, 10% of patients had a relapse within the first 6 months and another 8% had a relapse more than 6 months after receiving the vaccine. on follow-up for the patient who didn't have a frank relapse, within the first 6 months after receiving the vaccine 8% of patients had more than 50% reduction from their baseline platelet count and 6% had a 25-50% reduction in the platelets count. on follow-up more than 6 months after the vaccine,4% of patients had more than 50% reduction in platelet count and 3% had a 25-50% reduction from their baseline platelet count. There was no statically significant difference between Moderna and Pfizer vaccine on ITP relapse rate or platelet count reduction. Conclusion mRNA covid vaccine increases the risk of ITP relapse and leads to a reduction in platelets count compared to the baseline count before receiving the vaccine, with no statically significant difference between Pfizer and Moderna vaccines. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal