Abstract 51: Age Stratified Risk Of Cerebral Venous Sinus Thrombosis After Sars-Cov-2 Vaccination

Abstract

Introduction: Cerebral Venous Sinus Thrombosis (CVST) as a part of the thrombosis and thrombocytopenia syndrome is a rare adverse drug reaction of SARS-CoV-2 vaccination. The estimated background rate of CVST in adults is around 1 case per million per month, and CVST with thrombocytopenia accounts for 8% of all CVST. We assessed the age-stratified risk of CVST with and without thrombocytopenia after SARS-CoV-2 vaccination. Methods: We estimated the absolute risk of any CVST, CVST with thrombocytopenia, and CVST without thrombocytopenia, within 28 days of first dose SARS-CoV-2 vaccination, using data from the European Medicines Agency’s EudraVigilance database (until 13 June 2021). As a denominator, we used data on vaccine delivery from 31 European countries. For 22.8 million adults from 25 countries we estimated the absolute risk of CVST after the first dose of ChAdOx1 nCov-19 per age category. Results: The absolute risk of CVST within 28 days of first dose vaccination was 7.5 (95%CI 6.9-8.3), 0.7 (95%CI 0.2-2.4), 0.6 (95%CI 0.5-0.7) and 0.6 (95%CI 0.3-1.1) per million of first doses of ChAdOx1 nCov-19, Ad26.COV2.S, BNT162b2 and mRNA-1273, respectively. The absolute risk of CVST with thrombocytopenia within 28 days of first dose vaccination was 4.4 (95%CI 3.9-4.9), 0.7 (95%CI 0.2-2.4), 0.0 (95%CI 0.0-0.1) and 0.0 (95%CI 0.0-0.2) per million of first doses of ChAdOx1 nCov-19, Ad26.COV2.S, BNT162b2 and mRNA-1273, respectively. In recipients of ChAdOx1 nCov-19, the risk of CVST, both with and without thrombocytopenia, was the highest in the 18-24 years age group (7.3 per million, 95%CI 2.8-18.8 and 3.7, 95%CI 1.0-13.3, respectively). The risk of CVST with thrombocytopenia was the lowest in ChAdOx1 nCov-19 recipients ≥70 years (0.2, 95%CI 0.0-1.3). Age <60 compared to ≥60 was a predictor for CVST with thrombocytopenia (incidence rate ratio 5.79; 95%CI 2.98-11.24, p<0.001). Discussion: The risk of CVST with thrombocytopenia within 28 days of first dose vaccination with ChAdOx1 nCov-19 was higher in younger age groups. The risk of CVST with thrombocytopenia was slightly increased in patients receiving Ad26.COV2.S, comparing with the estimated background risk. The risk of CVST with thrombocytopenia was not increased in recipients of mRNA vaccines for SARS-CoV-2.