There is a much greater risk for blood clots in the brain due to COVID-19 infection than against vaccines against the disease, British researchers said on Thursday after the explosion of vaccinations was interrupted by reports of rare blood clots.
AstraZeneca (AZN.L) and Johnson & Johnson (JNJ.N) have both seen very rare reports of cerebral venous sinus thrombosis (CVST) related to their vaccines. On Wednesday, the United States suspended vaccinations with J & J’s shot while investigating a connection with blood clots, with Denmark dropping AstraZeneca’s shot on the issue.
British and European regulators have emphasized that the benefits of vaccination outweigh the risks.
A study among 500,000 COVID-19 patients found that CVST occurred at a rate of 39 people out of a million after infection. This can be compared to figures from the European Medicines Agency (EMA) which shows that 5 out of a million people reported CVST after receiving AstraZeneca.
The researchers said in a pre-printed study that the risk of CVST after the COVID-19 infection was 8-10 times higher than existing vaccines for the disease.
“The risk of having a (CVST) after COVID-19 appears to be significantly and significantly higher than after receiving the Oxford-AstraZeneca vaccine,” Maxime Taquet of the Oxford Department of Psychiatry told reporters.
The study was based on a US health database and therefore did not directly build up new data on the risk of blood clots from AstraZeneca’s vaccine, as the shot is not rolled out there.
Taquet said the death rate from CVST was about 20%, whether it occurred after COVID-19 infection or a vaccine, indicating that the blood clots were the main risk factor.
Regulators have also observed low platelet levels in reports of side effects of vaccines, but the researchers said the data are limited or this is also the case in those who report CVST after infection.
The researchers stressed that COVID-19 is associated with more common coagulation disorders than CVST, such as strokes, and that recent debate over vaccines has lost sight of how bad the disease itself can be.
“The importance of this finding is that the fact that it is a terrible disease has a whole range of consequences including an increased risk of (CVST),” said John Geddes, director of the NIHR Oxford Health Biomedical Research Center. said.
The Oxford University research team said they worked independently of the Oxford vaccine team that developed the AstraZeneca survey.
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