Thrombosis after corona vaccination: relevance of anticoagulants
After vaccinations against the SARS-CoV-2 coronavirus or the COVID-19 disease caused by the pathogen, thrombosis has occurred in rare cases. Researchers have now investigated the suitability of anticoagulants (anticoagulants; popularly: anticoagulants) for this life-threatening condition.
Researchers recently reported that they have deciphered a cause of thrombosis after corona vaccinations. A study now provides new information about this dangerous disease, which occurs in rare cases after such vaccination. The results of the study have been published in the journal Blood.
Vaccine-induced thrombotic thrombocytopenia
As noted in a recent report from the University Hospital of Tübingen, the increasing number of vaccinations against SARS-CoV-2 has been accompanied by reports of very rare but serious side effects from the vaccination.
In some of the most severe cases, life-threatening thrombotic events have occurred in unusual locations. According to the information, this condition is known as vaccine-induced thrombotic thrombocytopenia (VITT).
The anticoagulant heparin is very fast-acting, inexpensive, and readily available, making it one of the most commonly used anticoagulants to prevent and treat thrombotic events.
The use of heparin is sometimes discouraged
However, the pathophysiology of VITT has been shown to resemble heparin-induced thrombocytopenia (HIT) and is associated with platelet-activating antibodies against platelet factor 4 (PF4 for short).
HIT is understood as a complication of heparin therapy, which leads to a reduction in the number of platelets and a simultaneous tendency to thrombosis. Due to the similarities between VITT and HIT, the use of heparin to treat thrombosis in VITT patients is therefore not recommended.
In the present study, Dr. Anurag Singh and a team around Prof. Dr. Tamam Bakchoul from the Institute for Clinical and Experimental Transfusion Medicine (IKET) at Tübingen University Hospital examined the role of anticoagulants in patients who developed thrombosis in unusual locations after corona vaccination.
Thrombus formation can be slowed down
Researchers analyzed the binding between VITT and PF4 antibodies, platelet activation by VITT patient serum, and VITT antibody-mediated thrombus formation.
The experts’ results show that the interaction of heparin with VITT antibodies is not comparable to that of HIT. Unlike HIT, heparin can slow thrombus formation by VITT sera in vitro, in part by inhibiting the interaction of VITT antibodies with PF4 and subsequent platelet activation.
“We were able to demonstrate that VITT antibodies do not have the same effect as HIT antibodies in the presence of heparin. The VITT antibodies did not show increased binding with heparin and the antibody-PF4 complexes were successfully degraded by heparin”, explains Prof. Bakchoul.
Policies could be reconsidered
Based on these results, recommendations for the use of heparin in VITT patients could be reconsidered. “There are a few small cohort studies and clinical reports showing successful treatment of VITT patients with heparin,” Dr. Singh said.
“Because heparin is the most widely used anticoagulant, further clinical trials will provide a better understanding and easier management of this condition, even in hospitals where non-heparin anticoagulants are not readily available.”
However, this requires prospective clinical studies to verify the effectiveness of heparin in VITT patients, says Professor Bakchoul.
The mechanisms underlying the interaction between anticoagulants and VITT or HIT antibodies and the involvement of other immune cells in subsequent thromboinflammation are currently being investigated in other studies.
The current study is also the subject of an editorial in the journal Blood and the journal’s podcast. (ad)
Author and source information
This text corresponds to the specifications of the specialized medical literature, medical guidelines and current studies and has been verified by health professionals.
University Hospital Tübingen: New findings on thrombosis after corona vaccination, (accessed: June 26, 2022), University Hospital TübingenAnurag Singh, Filip Toma, Günalp Uzun, Teresa R. Wagner, Lisann Pelzl, Jan Zlamal, Verena Freytag, Karoline Weich, Stefanie Nowak-Harnau, Ulrich Rothbauer, Karina Althaus, Tamam Bakchoul: The interaction between anti-PF4 antibodies and anticoagulants in vaccine-induced thrombotic thrombocytopenia; bleeding; published: 06/09/2022), BloodDonald M. Arnold: heparinic or non-heparinic anticoagulants for VITT; bleeding; published: 09.06.2022), BloodBlood: Podcast: Anti-PF4 antibodies after Covid vaccination, CAR T-cell therapy for CNS leukemia and progress in Diamond-Blackfan anemia; (posted: 09/06/2022), Blood
This article contains general advice only and should not be used for self-diagnosis or treatment. It cannot substitute a visit to the doctor.