The risk of developing rare blood clots is higher for people who get COVID-19 than for those vaccinated, according to a study published Thursday by Oxford University.
The likelihood of cerebral sinus vein thrombosis – the condition that prompted federal health officials to discontinue use of the Johnson & Johnson vaccine this week – is up to 10 times higher after being infected with the coronavirus than after receiving an injection, according to the study.
[Findings] must be taken into account when weighing the balance between risks and benefits for vaccination, ”said Paul Harrison, head of the Translational Neurobiology Group in Oxford, at a news conference Thursday.
In the study, which was used to develop the AstraZeneca vaccine in Europe, researchers looked at the rate of coagulation in the two weeks after a COVID-19 diagnosis.
They also examined how many people suffered from the condition two weeks after a single dose of the Pfizer, Moderna and AstraZeneca vaccines was given.
Researchers found that the risk of developing the condition was 10 times higher after contracting COVID-19 than after receiving the Pfizer or Moderna shots, and eight times higher after receiving the AstraZeneca shot.
The study included no data on the Johnson & Johnson vaccine, which was interrupted by federal health officials Tuesday after six women reported suffering from the clotting disorder, including a 45-year-old who died.
Like the Johnson & Johnson vaccine in the US, the AstraZeneca shot has come under fire for possible links to blood clotting in Europe.
Denmark has stopped using AstraZeneca after a probe showed “real and serious side effects,” health officials said. Other countries have limited the use of the vaccine to older age groups, who seem to have less problems with blood clots.