Rare COVID Vaccine Clotting Linked to Adenoviral Protein

Antibody proteomics and immunogenetics identify adenoviral protein VII as the trigger of PF4-targeting antibodies

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Researchers identified the molecular trigger for rare clotting linked to adenoviral COVID-19 vaccines, targeting platelet factor 4 (PF4).
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The study addresses vaccine-induced immune thrombocytopenia and thrombosis (VITT), a syndrome first noted in 2021 after adenoviral vector vaccine rollout.
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Adenoviral core protein VII (pVII) was identified as the likely antigen inciting the immune response that mistakenly targets PF4.
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Nearly all patients with VITT shared a specific immunoglobulin light-chain variant and a somatic mutation known as K31E.
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Modifying or removing pVII in future vaccines could prevent this rare reaction while maintaining strong disease protection.

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