An Update on COVID-19 Vaccine Induced Thrombotic Thrombocytopenia Syndrome and Some Management Recommendations

• Published in: Molecules (Basel, Switzerland) Vol. 26; no. 16; p. 5004
• Main Authors: Islam, Amin, Bashir, Mohammed Sheraz, Joyce, Kevin, Rashid, Harunor, Laher, Ismail, Elshazly, Shereen
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 18.08.2021; MDPI
• Subjects: Adenoviruses; Antibodies - blood; Anticoagulants; Asymptomatic; Coronaviruses; COVID-19; COVID-19 vaccine; COVID-19 vaccines; COVID-19 Vaccines - adverse effects; Cytokines; Diagnosis, Differential; disseminated intravascular coagulation; Embolism; Fibrinogen; Fibrinolysis; Health risks; Heparin; Heparin - adverse effects; heparin induced thrombocytopenia; Humans; Infections; Ischemia; Pathophysiology; Patients; Platelet factor 4; Platelet Factor 4 - blood; Review; Risk analysis; Risk factors; Severe acute respiratory syndrome coronavirus 2; Surfactants; Thrombocytopenia; Thrombocytopenia - chemically induced; Thrombocytopenia - etiology; Thrombocytopenia - therapy; Thromboembolism; Thrombosis; Thrombosis - chemically induced; Thrombosis - etiology; Thrombosis - therapy; Vaccines; Viral infections; Viruses; Beijing China; Scotland; United Kingdom > UK; United States > US; China; Russia; COVID-19; vaccine induced thrombocytopenia and thrombosis; thrombosis; platelet factor 4; heparin induced thrombocytopenia; COVID-19 vaccine; thrombotic thrombo-cytopenic purpura; disseminated intravascular coagulation
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26165004

The thrombotic thrombocytopenia syndrome (TTS), a complication of COVID-19 vaccines, involves thrombosis (often cerebral venous sinus thrombosis) and thrombocytopenia with occasional pulmonary embolism and arterial ischemia. TTS appears to mostly affect females aged between 20 and 50 years old, with no predisposing risk factors conclusively identified so far. Cases are characterized by thrombocytopenia, higher levels of D-dimers than commonly observed in venous thromboembolic events, inexplicably low fibrinogen levels and worsening thrombosis. Hyper fibrinolysis associated with bleeding can also occur. Antibodies that bind platelet factor 4, similar to those associated with heparin-induced thrombocytopenia, have also been identified but in the absence of patient exposure to heparin treatment. A number of countries have now suspended the use of adenovirus-vectored vaccines for younger individuals. The prevailing opinion of most experts is that the risk of developing COVID-19 disease, including thrombosis, far exceeds the extremely low risk of TTS associated with highly efficacious vaccines. Mass vaccination should continue but with caution. Vaccines that are more likely to cause TTS (e.g., Vaxzevria manufactured by AstraZeneca) should be avoided in younger patients for whom an alternative vaccine is available.