• Clinical and Experimental Pediatrics
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• v.64 no.8
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• pp.400-405
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• 2021

The development of vaccines against severe acute respiratory syndrome coronavirus 2, which features high mortality and morbidity rates, has progressed at an unprecedented rate, and vaccines are currently in use worldwide. Thrombotic events after vaccination are accompanied by thrombocytopenia, and this issue was recently termed vaccine-induced immune thrombotic thrombocytopenia. This manuscript describes recently published guidelines and other related issues and demonstrates characteristic cases.

• Clinical and Experimental Vaccine Research
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• v.12 no.4
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• pp.265-290
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• 2023

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 included. 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 COVID-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 thrombosis, respectively. As there is emerging knowledge on and refinement of the published guidelines regarding VITT, this review may assist the medical communities in early VITT recognition, understanding the clinical presentations, diagnostic criteria as well as its management, offering a window of opportunity to VITT patients. Further larger sample size trials could further elucidate the link and safety profile.

• Clinical and Experimental Vaccine Research
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• v.11 no.3
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• pp.294-297
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• 2022

Monitoring of side effects after coronavirus disease 2019 (COVID-19) vaccination has become an important issue for health systems worldwide to ensure its safety. Recently cases of deep vein thrombosis (DVT), vaccine-induced immune thrombotic thrombocytopenia, and autoimmune hepatitis have been described: the underlying pathophysiological mechanisms are still debated. We report on a patient who presented with DVT and acute hepatitis 8 days after receiving the first dose of the ChAdOx1 nCoV-19 adenoviral vector vaccine against COVID-19. The patient is a 56-year-old male who was already affected by a rare form of axonal Charcot-Marie-Tooth disease linked to MME (membrane metalloendopeptidase) gene variation and associated with mild symptoms. His blood exams did not have any evidence of thrombocytopenia but D-dimer, troponin T, alanine transaminase, and aspartate aminotransferase were abnormal, suggesting the presence of a blood clot and acute hepatitis. The patient was treated with subcutaneous enoxaparin for 15 days and with rivaroxaban for the following 8 months: his symptoms improved and his exams showed recanalization of the veins and a healed liver. The pathogenesis of thrombosis and hepatitis after vaccination is still unclear, especially in subjects affected by rare comorbidities and this may affect the safety of vaccination in this type of population. We highlight the importance of careful monitoring of side effects after vaccination: clinical suspicion must rise when patients complain of symptoms that differ from their usual presentation.

• Korean Circulation Journal
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• v.54 no.6
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• pp.295-310
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• 2024

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 has led to a global health crisis with substantial mortality and morbidity. To combat the COVID-19 pandemic, various vaccines have been developed, but unexpected serious adverse events including vaccine-induced thrombotic thrombocytopenia, carditis, and thromboembolic events have been reported and became a huddle for COVID-19 vaccination. Vaccine-related myocarditis (VRM) is a rare but significant adverse event associated primarily with mRNA vaccines. This review explores the incidence, risk factors, clinical presentation, pathogenesis, management strategies, and outcomes associated with VRM. The incidence of VRM is notably higher in male adolescents and young adults, especially after the second dose of mRNA vaccines. The pathogenesis appears to involve an immune-mediated process, but the precise mechanism remains mostly unknown so far. Most studies have suggested that VRM is mild and self-limiting, and responds well to conventional treatment. However, a recent nationwide study in Korea warns that severe cases, including fulminant myocarditis or death, are not uncommon in patients with COVID-19 VRM. The long-term cardiovascular consequences of VRM have not been well understood and warrant further investigation. This review also briefly addresses the critical balance between the substantial benefits of COVID-19 vaccination and the rare risks of VRM in the coming endemic era. It emphasizes the need for continued surveillance, research to understand the underlying mechanisms, and strategies to mitigate risk. Filling these knowledge gaps would be vital to refining vaccination recommendations and improving patient care in the evolving COVID-19 pandemic landscape.