London – A study by researchers at the University of Oxford in England suggests that the risks of dangerous, rare blood clots in the brain are much higher in those who catchthan those receiving either the AstraZeneca vaccine or vaccines produced by Pfizer and Moderna in the United States. Studies show that the number of people who experience clots after receiving vaccines made by US pharmaceutical giants looks very similar to the number who get the rare condition after a shot of the drug AstraZeneca, developed in collaboration with the Oxford Vaccine Institute.
A key finding of the study, unveiled on Thursday as a pre-print study to be reviewed by other scientists, is that the risk of a blood clot in the brain is about 95 times higher for people who become infected with COVID 1
This is another serious health threat associated with the disease, and one that scientists hope will boost confidence in all major vaccines currently available in the Western world, as their research shows that drugs carry a significantly lower threat than clotting than the disease that has been shown to fend off.
The analysis of real-world data collected by the global health research network TriNetX and European agencies includes information on hundreds of thousands of people who have caught COVID-19 or received, Photos by Pfizer or Moderna. Most of the data on mRNA vaccines, which are US drugs, are from the United States, while data on AstraZeneca shots come largely from European mass vaccination programs.
The data show that about 4 out of every 1 million people who receive US vaccines experience cerebral venous thrombosis (CVT) or blood clots in the brain. With the AstraZeneca vaccine, which works differently and is similar to, the study shows a frequency of about 5 per 1 million.
This equates to a risk of CVT 10 times higher for people who catch coronavirus than for those who receive Pfizer or Moderna vaccines, and 8 times higher for those who receive a shot of AstraZeneca.
“There are concerns about possible links between vaccines and CVD, which are prompting governments and regulators to limit the use of some vaccines,” said Paul Harrison, a professor of psychiatry and head of the Oxford Group on Translational Neurobiology. “We came to two important conclusions. First, COVID-19 significantly increases the risk of CVD, adding to the list of blood clotting problems that this infection causes. Second, the risk of COVID-19 is higher than current vaccines, even for those under 30; something to consider when balancing the risks and benefits of vaccination. “
A study published by Oxford on Thursday found that about 39 out of every 1 million people infected with COVID-19 are likely to get brain clots. The researchers emphasized that the aim of their study was not to compare vaccines, but to collect solid data on the risks of all vaccines compared to the risks associated with catching COVID-19.
“The signals that COVID-19 is associated with CVT, as well as portal vein thrombosis – a disorder of liver clotting – are clear and one thing to consider,” said Dr Maxime Taquet, another researcher in the translational neurobiology.
As the figures used to determine the overall incidence rate are constantly updated, the researchers emphasize that “all comparisons must be interpreted carefully, as data are still accumulating”.
They also noted that it was not yet clear whether “COVID-19 and vaccines lead to CVD by the same or different mechanisms” and said that this would be the subject of ongoing research.