Deterioration of vaccine-induced immune thrombotic thrombocytopenia treated by heparin and platelet transfusion: Insight from functional cytometry and serotonin release assay

Vaccine-induced immune thrombotic thrombocytopenia: what do we know hitherto?

Vaccine-induced immune thrombotic thrombocytopenia (VITT), also known as thrombosis with thrombocytopenia syndrome, is a catastrophic and life-threatening reaction to coronavirus disease 2019 (COVID-19) vaccines, which occurs disproportionately in response to vaccination with non-replicating adenovirus vector (AV) vaccines. The mechanism of VITT is not well defined and it has not been resolved why cases of VITT are predominated by vaccination with AV vaccines. However, virtually all VITT patients have positive platelet-activating anti-platelet factor 4 (PF4) antibody titers. Subsequently, platelets are activated and depleted in an Fcγ-receptor IIa (FcγRIIa or CD32a)-dependent manner, but it is not clear why or how the anti-PF4 response is mounted. This review describes the pathogenesis of VITT and provides insight into possible mechanisms that prompt the formation of a PF4/polyanion complex, which drives VITT pathology, as an amalgam of current experimental data or hypotheses.

Lower limb arterial thrombosis followed by sub-massive pulmonary thromboembolism after Sinopharm BBIBP-CorV COVID-19 vaccination

The global COVID-19 vaccination had an undeniable influence on the pandemic management, despite of having reported rare but life-threatening side-effects of vaccines. Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare autoimmune complication determined by thrombocytopenia and thrombosis propensity in the circulatory system. The activation of antibodies against platelet factor-4 (PF-4) which mimics the heparin-induced thrombocytopenia (HIT) characteristic is the main known pathogenicity of the disease. Herein, we reported a case of VITT in a middle-aged woman with no previous history of thrombophilia or other medical conditions who presented with thrombosis of the left superficial femoral artery 3-days after receiving the second dose of inactivated BBIBP-CorV (Sinopharm) vaccine. The patient underwent bypass vascular surgery and received none-heparin anticoagulation consistent with high-dose intravenous immunoglobin. Eight days after the discharge, she was subsequently referred to our center with the presentation of sub-massive pulmonary thromboembolism in spite of receiving the prophylactic anticoagulants during follow-up period. Details on side-effects of COVID-19 vaccines, specifically the inactivated ones are yet to be fully ascertained. Clinicians should consider the history of COVID-19 vaccines in thromboembolism patients who do not have well-acknowledged risk factors. Further studies about the necessity of prophylactic anticoagulants and clinical judgment for receiving other vaccines in such patients are required.

How Protective are Antibodies to SARS-CoV-2, the Main Weapon of the B-Cell Response?

Since the beginning of the Coronavirus disease (COVID)-19 pandemic in December 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been responsible for more than 600 million infections and 6.5 million deaths worldwide. Given the persistence of SARS-CoV-2 and its ability to develop new variants, the implementation of an effective and long-term herd immunity appears to be crucial to overcome the pandemic. While a vast field of research has focused on the role of humoral immunity against SARS-CoV-2, a growing body of evidence suggest that antibodies alone only confer a partial protection against infection of reinfection which could be of high importance regarding the strategic development goals (SDG) of the United Nations (UN) and in particular UN SDG3 that aims towards the realization of good health and well being on a global scale in the context of the COVID-19 pandemic.In this review, we highlight the role of humoral immunity in the host defense against SARS-CoV-2, with a focus on highly neutralizing antibodies. We summarize the results of the main clinical trials leading to an overall disappointing efficacy of convalescent plasma therapy, variable results of monoclonal neutralizing antibodies in patients with COVID-19 but outstanding results for the mRNA based vaccines against SARS-CoV-2. Finally, we advocate that beyond antibody responses, the development of a robust cellular immunity against SARS-CoV-2 after infection or vaccination is of utmost importance for promoting immune memory and limiting disease severity, especially in case of (re)-infection by variant viruses.

Vaccine-induced immune thrombotic thrombocytopenia after ChAdOx1 nCoV-19 vaccine in an older patient: Minireview and a case report

Rare cases of unusual thrombosis and thrombocytopenia after administration of the ChAdOx1 nCoV-19 vaccine (AstraZeneca) have been reported. The unusual symptoms are called vaccine-induced immune thrombotic thrombocytopenia (VITT). In the present study, a brief background about cases of unusual thrombosis and thrombocytopenia after administration of the ChAdOx1 nCoV-19 was provided. In addition, a description of a case of a 66-year-old woman who had received this vaccine and developed VITT was done. She presented to the hospital complaining of hematomas in the right upper limb 14 days after the ChAdOx1 nCoV-19 vaccine, without a history of trauma (Glasgow coma scale of 14) and thrombocytopenia even though signs of thrombosis were absent. Cranium computed tomography scan indicated intraparenchymal hematoma and cerebral thrombosis, besides anastomotic Labbé vein thrombosis. The woman received platelets transfusion, dexamethasone, and neuroprotection measures, but even so, on the twelfth postoperative day, she died of cerebral rebleeding. In conclusion, it is crucial to point out the immuno-hypersensitivity mechanisms associated with ChAdOx1 nCoV-19 vaccine reactions, helping to reduce their occurrences and reinforcing confidence in vaccine administration.

Subarachnoid hemorrhage: management considerations for COVID-19

Subarachnoid hemorrhage (SAH) has deleterious outcomes for patients, and during the hospital stay, patients are susceptible to vasospasm and delayed cerebral ischemia. Coronavirus disease 2019 (COVID-19) has been shown to worsen hypertension through angiotensin-converting enzyme 2 (ACE2) activity, therefore, predisposing to aneurysm rupture. The classic renin-angiotensin pathway activation also predisposes to vasospasm and subsequent delayed cerebral ischemia. Matrix metalloproteinase 9 upregulation can lead to an inflammatory surge, which worsens outcomes for patients. SAH patients with COVID-19 are more susceptible to ventilator-associated pneumonia, reversible cerebral vasoconstriction syndrome, and respiratory distress. Emerging treatments are warranted to target key components of the anti-inflammatory cascade. The aim of this review is to explore how the COVID-19 virus and the intensive care unit (ICU) treatment of severe COVID can contribute to SAH.

Stroke Associated with COVID-19 Vaccines

Objectives

Development of safe and effective vaccines against coronavirus disease 2019 (COVID-19) remains the cornerstone of controlling this pandemic. However, there are increasing reports of various types of stroke including ischemic stroke, and hemorrhagic stroke, as well as cerebral venous sinus thrombosis (CVST) after COVID-19 vaccination. This paper aims to review reports of stroke associated with COVID-19 vaccines and provide a coherent clinical picture of this condition.

Materials and methods

A literature review was performed with a focus on data from recent studies.

Results

Most of such patients are women under 60 years of age and who had received ChAdOx1 nCoV-19 vaccine. Most studies reported CVST with or without secondary ischemic or hemorrhagic stroke, and some with Vaccine-induced Thrombotic Thrombocytopenia (VITT). The most common clinical symptom of CVST seen after COVID-19 vaccination was headache. The clinical course of CVST after COVID-19 vaccination may be more severe than CVST not associated with COVID vaccination. Management of CVST following COVID-19 vaccination is challenging and may differ from the standard treatment of CVST. Low molecular weight heparin is commonly used in the treatment of CVST; however, it may worsen outcomes in CVST associated with VITT. Furthermore, administration of intravenous immunoglobulin and high-dose glucocorticoids have been recommended with various success rates.

Conclusion

These contradictory observations are a source of confusion in clinical decision-making and warrant further study and development of clinical guidelines. Clinicians should be aware of clinical presentation, diagnosis, and management of stroke associated with COVID-19 vaccination.

COVID-19, Vaccines, and Thrombotic Events: A Narrative Review

The coronavirus disease 2019 (COVID-19), a deadly pandemic that has affected millions of people worldwide, is associated with cardiovascular complications, including venous and arterial thromboembolic events. Viral spike proteins, in fact, may promote the release of prothrombotic and inflammatory mediators. Vaccines, coding for the spike protein, are the primary means for preventing COVID-19. However, some unexpected thrombotic events at unusual sites, most frequently located in the cerebral venous sinus but also splanchnic, with associated thrombocytopenia, have emerged in subjects who received adenovirus-based vaccines, especially in fertile women. This clinical entity was soon recognized as a new syndrome, named vaccine-induced immune thrombotic thrombocytopenia, probably caused by cross-reacting anti-platelet factor-4 antibodies activating platelets. For this reason, the regulatory agencies of various countries restricted the use of adenovirus-based vaccines to some age groups. The prevailing opinion of most experts, however, is that the risk of developing COVID-19, including thrombotic complications, clearly outweighs this potential risk. This point-of-view aims at providing a narrative review of epidemiological issues, clinical data, and pathogenetic hypotheses of thrombosis linked to both COVID-19 and its vaccines, helping medical practitioners to offer up-to-date and evidence-based counseling to their often-alarmed patients with acute or chronic cardiovascular thrombotic events.