Declining mortality of cerebral venous sinus thrombosis with thrombocytopenia after SARS-CoV-2 vaccination.

van de Munckhof, Anita; Krzywicka, Katarzyna; Aguiar de Sousa, Diana; Sánchez van Kammen, Mayte; Heldner, Mirjam R; Jood, Katarina; Lindgren, Erik; Tatlisumak, Turgut; Putaala, Jukka; Kremer Hovinga, Johanna A; Middeldorp, Saskia; Levi, Marcel; Arnold, Marcel; Ferro, José M; Coutinho, Jonathan M

BACKGROUND High mortality rates have been reported in patients with cerebral venous sinus thrombosis (CVST) due to vaccine-induced immune thrombotic thrombocytopenia (VITT) after vaccination with adenoviral vector SARS-CoV-2 vaccines. The aim of this study was to evaluate whether mortality of patients with CVST-VITT has decreased over time. METHODS We used the EudraVigilance database of the European Medicines Agency to identify cases of CVST with concomitant thrombocytopenia occurring within 28 days of SARS-CoV-2 vaccination. Vaccines were grouped based on vaccine type (adenoviral or mRNA). Cases with CVST onset until 28 March were compared to cases after 28 March 2021, which was the day when the first scientific paper on VITT was published. RESULTS We identified 270 cases of CVST with thrombocytopenia, of which 266 (99%) occurred after adenoviral vector SARS-CoV-2 vaccination (ChAdOx1 nCoV-19 n=243, Ad26.COV2.S n=23). Reported mortality among adenoviral cases with onset up to 28 March 2021 was 47/99 (47%, 95%CI 37-58%) compared to 36/167 (22%, 95%CI 16-29%) in cases with onset after 28 March (p=<0.001). None of the 4 cases of CVST with thrombocytopenia occurring after mRNA vaccination died. CONCLUSION Reported mortality of CVST with thrombocytopenia after vaccination with adenoviral vector-based SARS-CoV-2 vaccines has significantly decreased over time, which may indicate a beneficial effect of earlier recognition and/or improved treatment on outcome after VITT.