COVID-19 vaccine-induced immune thrombotic thrombocytopenia: a review

• Published in: Clinical and Experimental Vaccine Research
• Main Author: Suhaimi S.N.A.A.; Zaki I.A.H.; Noordin Z.M.; Hussin N.S.M.; Ming L.C.; Zulkifly H.H.
• Format: Review
• Language: English
• Published: Korean Vaccine Society 2023
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85177854317&doi=10.7774%2fcevr.2023.12.4.265&partnerID=40&md5=69d883075587c1acfec268b331319d2b

Rare but serious thrombotic incidents in relation to thrombocytopenia, termed vaccine-induced immune thrombotic thrombocytopenia (VITT), have been observed since the vaccine rollout, particularly among replication-defective adenoviral vector-based severe acute respiratory syndrome coronavirus 2 vaccine recipients. Herein, we comprehensively reviewed and summarized reported studies of VITT following the coronavirus disease 2019 (COVID-19) vaccination to determine its prevalence, clinical characteristics, as well as its management. A literature search up to October 1, 2021 using PubMed and SCOPUS identified a combined total of 720 articles. Following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline, after screening the titles and abstracts based on the eligibility criteria, the remaining 47 full-text articles were assessed for eligibility and 29 studies were in-cluded. Findings revealed that VITT cases are strongly related to viral vector-based vaccines, which are the AstraZeneca COVID-19 vaccine (95%) and the Janssen COVID-19 vaccine (4%), with much rarer reports involving messenger RNA-based vaccines such as the Moderna CO-VID-19 vaccine (0.2%) and the Pfizer COVID-19 vaccine (0.2%). The most severe manifestation of VITT is cerebral venous sinus thrombosis with 317 cases (70.4%) and the earliest primary symptom in the majority of cases is headache. Intravenous immunoglobulin and non-heparin anticoagulant are the main therapeutic options for managing immune responses and throm-bosis, respectively. As there is emerging knowledge on and refinement of the published guide-lines regarding VITT, this review may assist the medical communities in early VITT recognition, understanding the clinical presentations, diagnostic criteria as well as its management, of-fering a window of opportunity to VITT patients. Further larger sample size trials could further elucidate the link and safety profile. © Korean Vaccine Society.