Researchers at the University of Oxford said on Thursday that the risk of developing rare blood clots is higher after being infected with COVID-19 than it is for people who have been vaccinated.
The findings come in a new study published by the university, which helped develop the AstraZeneca vaccine now under scrutiny for possible links to a brain blood clot known as cerebral venous sinus thrombosis (CVST).
After comparing the number of CVST cases in the two weeks after a COVID-19 diagnosis and after the first dose of a vaccine, Oxford reports that the risk of developing blood clots is as much as ten times greater after a COVID- 19 infection if it is after a vaccination.
The researchers noted that compared to the Pfizer and Moderna vaccines, the risk of developing CVST is about ten times greater, while the risk is about eight times higher than compared to the Oxford-AstraZeneca vaccine.
While the study notes that data on possible links between the vaccines and blood clots is still under scrutiny, Paul Harrison, head of Oxford’s Translational Neurobiology Group, said Thursday’s findings should be taken into account when balancing risks and benefits for vaccination are considered. . ”
The study comes after a spate of countries restricted the use of AstraZeneca’s vaccine to older age groups due to reports of blood clots.
On Wednesday, Denmark became the first European country to stop completely the use of the AstraZeneca shot after an examination “Has shown real and serious side effects,” according to the Danish Health Authority.
A European Medicines Agency (EMA) safety committee said last week that a ‘possible link’ exists between the AstraZeneca vaccine and blood clots, although it added that the benefits of vaccination to protect COVID-19 outweigh the risks.
The Oxford study does not include data on the shot of Johnson & Johnson, which was interrupted in the US on the recommendation of health authorities reviewing six cases of blood clots among the 7 million people who received the shot.
An independent advisory group for the Centers for Disease Control and Prevention on Wednesday postponed making a recommendation on the Johnson & Johnson shot until there was more evidence of blood clots, which is likely to prolong the spread of one of the three coronavirus vaccines. federally approved for emergency use in the US