Genetic mutation explains rare blood clots after adenovirus-based COVID-19 vaccines

Researchers identified a genetic mutation that caused a rare blood-clotting disorder in a small group of people after receiving certain COVID-19 vaccines. The mutation alters antibodies, causing them to attack a blood-clotting protein called PF4, leading to severe clotting and low platelet counts. This occurred in individuals previously exposed to adenovirus, used in J&J and AstraZeneca vaccines. This discovery marks the first time an autoimmune disorder has been traced to a specific triggering event, offering insights into vaccine safety and rare adverse reactions.