ChAdOx1 nCoV-19 Vaccine and Thrombosis with Thrombocytopenia Syndrome among Adults: A Systematic Review

Several vaccine-induced thrombotic thrombocytopenia syndrome (VITTS) cases have been reported after the ChAdOx1 nCov-19 vaccination. The current study systematically reviewed post-ChAdOx1 nCoV-19 vaccination cases. Their laboratory and clinical features, as well diagnostic therapeutic measures, were investigated. Online databases searched until 25 August 2021. Studies reporting TTS included. Overall, 167 (21-77 years old) from 53 publications included showing a female dominance of 1.75 times. About 85% exhibited primary symptoms within first two weeks post-vaccination. Headache was most common initial symptom (>44.2%), hemorrhage/thrombotic problems (22.46%), discoordination/weakness/numbness/hemiparesis/cyanotic toes (19.6%), prevalent uncommon symptoms. Prothrombin time (PT), D-dimers, C-reactive protein remarkable increased parameters in 50.6%, 99.1%, 55.6% cases, respectively. In comparison, platelet fibrinogen decreased 92.7% 50.5% Most VITT presented with cerebral venous thrombosis (CVT)/cerebral sinus (CVST), supraventricular tachycardia (SVT), transverse sinus/cerebral thrombosis, pulmonary embolism (PE), hemorrhage. Anti-PF4 antibody measurement through immunoassays functional assays positive 86.2% 73% 31% died. Early diagnosis proper measures are important VITTS patients. Therefore, experts recommended to know corresponding methods. Elucidation pathophysiologic mechanism deserves further investigation.