Skip to main content

New study suggests blood group may predict the risk of stroke when receiving Covid-19 Oxford-AstraZeneca vaccination

New study suggests blood group may predict the risk of stroke when receiving Covid-19 Oxford-AstraZeneca vaccination

  • Date13 December 2023

A large international research collaboration, led by an academic from Royal Holloway, University of London, found that blood groups could help predict the risk of venous strokes associated with the Oxford-AstraZeneca Covid-19 vaccine.

Coronavirus 2.Tmb 479V

The research was led by Professor Pankaj Sharma from the Institute of Cardiovascular Research at Royal Holloway and the Department of Clinical Neurology at Imperial College Healthcare NHS Trust, along with a collaborative group of researchers from across the globe.

The study, published in the Journal of the Royal Society of Medicine, set out to determine whether a patient’s blood group influences the development of Cerebral Venous Thrombosis (CVT) – otherwise known as a venous stroke – following administration of the Oxford-AstraZeneca COVID-19 vaccine.

Previous research had found that patients with blood group A, were at a greater risk of severe COVID-19, as they constituted the majority of patients in intensive care. Any occurrence of CVT within 28 days of receiving the Oxford-AstraZeneca vaccine is defined internationally as being a result of the injection.

A total of 523 CVT patients were used in the study and recruited from two study groups investigating venous strokes. Of the total, 82 patients had suffered from CVT after receiving the Oxford-AstraZeneca vaccine, while the remaining 441 were unvaccinated CVT patients. Participants in the study had their blood group tested, and the results were compared to determine the distribution of blood groups in the vaccinated and unvaccinated patients.

The study found that blood group O was more prevalent in patients who had experienced a venous stroke after receiving the Oxford-AstraZeneca vaccine (43%) than it was in those patients who were unvaccinated venous stroke sufferers (17%). The researchers found that patients with blood group A were the most common by percentage among those in the unvaccinated group (71%).

The findings of the research suggest that those with blood group O have an increased risk of CVT, or venous stroke, following administration of the Oxford-AstraZeneca vaccine, regardless of well-established venous stroke risk factors – such as gender.

Further studies could help researchers to understand more about the relationship between patients from the O blood group and the apparent elevated risk of CVT after receiving the Oxford-AstraZeneca vaccine.

Professor Pankaj Sharma, from the Department of Biological Sciences at Royal Holloway, said: “Our work suggests that it may be possible to predict those most at risk of cerebral venous thrombosis stroke following COVID-19 vaccination using a simple test for blood group.

“The AstraZeneca vaccine is 10 times cheaper than mRNA vaccines such as Pfizer, yet many countries have paused its use because of this associated risk of stroke, despite the vaccine being highly effective and easily transportable.

“Those with blood group O, seem two-and-a-half times more likely to be in the post-vaccine risk group. Predicting who is more likely to suffer from stroke after vaccination may provide confidence to governments for using this vaccine – particularly in low- and middle-income countries, where cheaper and more easily-transportable vaccines could prove more effective.”

Explore Royal Holloway

Get help paying for your studies at Royal Holloway through a range of scholarships and bursaries.

There are lots of exciting ways to get involved at Royal Holloway. Discover new interests and enjoy existing ones.

Heading to university is exciting. Finding the right place to live will get you off to a good start.

Whether you need support with your health or practical advice on budgeting or finding part-time work, we can help.

Discover more about our 21 departments and schools.

Find out why Royal Holloway is in the top 25% of UK universities for research rated ‘world-leading’ or ‘internationally excellent’.

Royal Holloway is a research intensive university and our academics collaborate across disciplines to achieve excellence.

Discover world-class research at Royal Holloway.

Discover more about who we are today, and our vision for the future.

Royal Holloway began as two pioneering colleges for the education of women in the 19th century, and their spirit lives on today.

We’ve played a role in thousands of careers, some of them particularly remarkable.

Find about our decision-making processes and the people who lead and manage Royal Holloway today.