In 2021, several women in Europe suffered brain thrombosis after being vaccinated with AstraZeneca. Researchers have found the place where the immune system was misdirected in rare cases.
The Astrazeneca vaccine against Covid was not in use for long in 2021: in mid-March, several EU states stopped the vaccination. This, after five million people had already been vaccinated. Of all those vaccinated, 30 people had a blood clot in the vein that leads to the brain – the sinus vein. In Germany, for example, six cases were known – three women died. The substance was never approved in Switzerland.
“These cases of thrombosis must be clarified,” said Wolfgang Korte, board member of the Society for Thrombosis and Hemostasis Research and head of the Center for Laboratory Medicine in St.Gallen, to this newspaper at the time.
An international research team from Germany, Australia, the Netherlands and Canada has now solved the mystery; the study has been published in the New England Journal of Medicine: Only people who had a rare variant of a gene were at risk of suffering such a cerebral thrombosis. This mutation can mislead the immune system, causing people to produce antibodies and ultimately activate platelets after vaccination. Platelets are blood cells that normally only clump together when vascular injuries occur.