Cerebral Venous Sinus Thrombosis due to Vaccine-Induced Immune Thrombotic Thrombocytopenia in Middle-Income Countries.

Abstract

Adenovirus-based COVID-19 vaccines are extensively used in low- and middle-income countries (LMICs). Remarkably, cases of cerebral venous sinus thrombosis due to vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) have rarely been reported from LMICs. We studied the frequency, manifestations, treatment, and outcomes of CVST-VITT in LMICs. We report data from an international registry on CVST after COVID-19 vaccination. VITT was classified according to the Pavord criteria. We compared CVST-VITT cases from LMICs to cases from high-income countries (HICs). Until August 2022, 228 CVST cases were reported, of which 63 from LMICs (all middle-income countries [MICs]: Brazil, China, India, Iran, Mexico, Pakistan, Turkey). Of these, 32/63 (51%) met the VITT criteria, compared to 103/165 (62%) from HICs. Only 5/32 (16%) CVST-VITT cases from MICs had definite VITT, mostly because anti-PF4 antibodies were often not tested. Median age was 26 (IQR 20-37) vs 47 (IQR 32-58) years, and proportion of women was 25/32 (78%) vs 77/103 (75%) in MICs vs HICs, respectively. Patients from MICs were diagnosed later than patients from HICs (1/32 [3%] vs 65/103 [63%] diagnosed before May 2021). Clinical manifestations, including intracranial hemorrhage, were largely similar as was intravenous immunoglobulin use. In-hospital mortality was lower in MICs (7/31 [23%, 95%CI 11-40]) than HICs (44/102 [43%, 95%CI 34-53], p=0.039). The number of CVST-VITT cases reported from LMICs was small despite widespread use of adenoviral vaccines. Clinical manifestations and treatment of CVST-VITT cases were largely similar in MICs and HICs, while mortality was lower in patients from MICs.