Investigators at Greifswald University Hospital in Northern Germany said on Friday they had discovered the cause of the unusual blood clotting found in some recipients of the AstraZeneca coronavirus vaccine, public broadcaster Norddeutscher Rundfunk (NDR) reported.
The study showed how the vaccine caused rare brain thrombosis in a small number of patients.
The discovery means that targeted treatment can be offered to people with a similar clot, using a common medication.
Its success was the result of a collaboration between Greifswald Hospital, state health regulator the Paul Ehrlich Institute (PEI), and doctors in Austria – a nurse there died of brain thrombosis after being vaccinated with the AstraZeneca shot.
The researchers emphasized that treatment would only be possible in patients who develop blood clots, and not as a preventive treatment.
The information has been shared with hospitals across Europe.
Symptoms such as persistent headache, dizziness or impaired vision that persist for more than three days after vaccination need further medical checks, the German Research Association for Thrombosis and Hemostasis said in a statement on the recent findings.
Greifswald’s findings have not yet been published in any scientific journal and have therefore not been reviewed by independent experts. The Paul-Ehrlich Institute in Germany is now examining the work of the scientists.
AstraZeneca is getting back on track in Europe
Germany, along with several other EU member states, suspended the use of the AstraZeneca vaccine on Monday following reports of unusual blood clots.
On Thursday, the European Medicines Agency (EMA) said there was no proven link between the vaccine and the clots, based on the information they had. They also stated that the benefits of the injection outweighed the possible risks.
In response to the updated guidelines, Germany would re-vaccinate with the British-Swedish shot on Friday.
On Thursday, Germany had administered more than 10 million doses of COVID-19 vaccines, including the AstraZeneca vaccine.
DW’s Katja Sterzik contributed to this article.