Scientists world-wide are racing to understand why Covid-19 vaccines from AstraZeneca PLC and Johnson & Johnson are causing rare but potentially deadly blood clots. Determining the connection would help patients, doctors and health agencies better assess any risks posed by the vaccines and safely calibrate their use. According to Prof. Greinacher, that reaction could be tied to stray proteins and a preservative he has found in the AstraZeneca vaccine. Prof. Greinacher is working to confirm his theory, hoping to get cooperation from vaccine makers. His team has tested AstraZeneca vaccines and has just received doses from Johnson & Johnson.

Source: Fox News May 14, 2021 11:20 UTC