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New Study Links Genetic Factors to Vaccine Blood Clots

2/12/2026

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Summary

Story summary

In 2021, concerns arose about blood clotting linked to the AstraZeneca and Johnson & Johnson vaccines.
Authorities paused use of these vaccines and withdrew them.
A study in The New England Journal of Medicine linked VITT to an immune response to the vaccine's adenovirus and reported 60 U.S. and 455 U.K. cases.
Researchers identified genetic factors that predispose some individuals to VITT, suggesting these insights could improve safety and trust.

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Story summary

In 2021, concerns arose about blood clotting linked to the AstraZeneca and Johnson & Johnson vaccines.
Authorities paused use of these vaccines and withdrew them.
A study in The New England Journal of Medicine linked VITT to an immune response to the vaccine's adenovirus and reported 60 U.S. and 455 U.K. cases.
Researchers identified genetic factors that predispose some individuals to VITT, suggesting these insights could improve safety and trust.