German researchers on Wednesday said that based on laboratory research, they believed they have found the cause of the rare but serious blood clotting events among some people who received vaccines made by AstraZeneca and Johnson & Johnson.The researchers, in a study not yet reviewed by experts, said vaccines that employ adenovirus vectors — cold viruses used to deliver vaccine material — send some of their payload into the nucleus of cells, where some of the instructions for making coronavirus proteins can be misread. The resulting proteins could potentially trigger blood clot disorders in a small number of recipients, they suggest. J&J, in a statement said: “We are supporting continued research of this rare event as we work with medical experts and global health authorities.” AstraZeneca declined to comment.Researchers at the Goethe-University of Frankfurt and other sites explained in their paper that vaccines using a different technology known as messenger RNA (mRNA) deliver the genetic material of the coronavirus spike protein only to fluid found inside cells, not to the nucleus of the cells. “All mRNA-based vaccines should represent safe products,” the paper said.

Source: Economic Times May 28, 2021 01:06 UTC