The European Medicines Agency is aware of 62 cases of venous thrombosis in the cavernous sinus, which appear to be associated with the intake of the vaccine against Covid-19 registered in the European Economic Area (countries of the European Union as well as Iceland, Liechtenstein and Norway). This more than doubles the number of these types of thromboembolic phenomena, which are rare for those who were documented through March 18, when the EMA gave the go-ahead for this vaccine, despite promising more research on the subject.
These 62 cases were recorded in 9.2 million people who took a dose of the AstraZeneca vaccine in those countries, which represents a 1 in 100,000 risk of cerebral sinus thrombosis in a population under 60, said Emer Cooke, Director known from EMA. And those 62 cases are registered through March 22nd – there will be a new update next week, he said.
The incidence is higher in women under the age of 55 – but it’s not yet possible to tell if this is an effect of this sudden illness or if it is simply because more young women are being vaccinated in this population who are vaccinated against AstraZeneca, Emer explained Cooke. “The vast majority of cases are women, there is a 10 to 1 ratio,” he admitted and this is a disease that is more common in women too. The cases also focus on an age group he defines as “35 to 45 years old”.
However, the EMA is not yet ready to make a decision or make a recommendation on the use of this vaccine that is gender or age specific. “Our position has not changed. Based on current scientific knowledge, there is no indication of a decision to stop using this vaccine, ”said Emer Cooke. “So far, no explanation has been found that links a previous clinical history of blood clots, gender or age of the person to the risk of these thromboembolic events,” he said.
The initial analysis resulted in an update of the vaccine leaflet, which included warning signs to look out for after vaccination and recommending immediate medical attention: shortness of breath, chest pain, leg swelling and persistent abdominal pain after vaccination.
However, some studies have linked these sudden illness phenomena after taking the vaccine to disorders involving blood clots and bleeding caused by a decrease in the number of platelets, which are rare but treatable – as suggested by Andreas Greinacher’s team University of Greifswald, which says it resembles heparin-induced thrombocytopenia.
Emer Cooke said these studies will be analyzed at the meeting, April 6-9, of the EMA Pharmacovigilance and Risk Assessment Committee, which is responsible for analyzing safety issues of medicines for human use. He is working on the assessment of this case and should make a new recommendation at the end of this meeting.
However, several countries have chosen to reserve the AstraZeneca vaccine only for people over 55, as the vast majority of these cases occur in younger people: Germany, Canada, France, Sweden, Finland, and Iceland.