AstraZeneca and Johnson & Johnson have both seen very rare reports of cerebral venous sinus thrombosis (CVST) linked to their vaccines. A study of 500,000 Covid patients found CVST had occurred at a rate of 39 people out of a million following infection, researchers said. That compares with European Medicines Agency figures showing that 5 in a million people reported CVST after getting AstraZeneca’s shot.
The researchers said in a pre-print study that the risk of CVST was 8-10 times higher following Covid than it was from existing vaccines for the disease. “The risk of having a (CVST) after Covid appears to be substantially higher than it is after receiving the Astra vaccine,” Maxime Taquet of Oxford’s department of psychiatry said.
The study was based on a US health database, and so did not accrue new data on the risk of clots from Astra’s vaccine directly, as the shot is not being rolled out there. Taquet said the mortality rate from CVST was around 20% whether it occurred after Covid infection or a vaccine.