Strokes can be caused by a range of factors, including high blood pressure and obesity, but vaccine skeptics and conspiracy theorists have been quick to link this increase to the global rollout of COVID-19 vaccines, which began in December 2020.

The Claim

The research, published by the University of Oxford, has been shared within conspiratorial communities on Reddit and Twitter as evidence that the COVID-19 vaccine is responsible for the observed increase in stroke rates among young people.

A tweet by one user said: “Study reveals sharp rise in #stroke cases under the age of 55 following #convid #vaccine…shock.”

These assertions come in the wake of the widely publicized stroke of Democratic Senate nominee, John Fetterman, which some onlookers claim was a direct result of his COVID-19 vaccination.

“Remember that time John Fetterman proudly got the vaccine shots before he had a stroke?” said one user on Twitter.

The Facts

Although the aforementioned study was published in 2022, the data used in the analysis was collected between 2002 and 2018, before the emergence of COVID-19 and its associated vaccine.

The reason for the observed rise in stroke incidence is currently unknown, but it is likely to be due to several factors.

“Many patients do still have the traditional vascular risk factors–obesity, hypertension, smoking–but there is also an increase in incidence in young adults of people with no risk factors and no obvious cause on investigation,” Peter Rothwell, one of the study’s co-authors, told Newsweek.

“Other factors, such as air pollution, psychological stress, or lack of exercise might [also] be important.”

COVID-19 vaccinations have been associated with a small increase in the risk of blood clots and heart inflammation, but a recent meta-analysis has confirmed that the proportion of people who suffer from ischemic strokes following vaccination is comparable to the prevalence of ischemic strokes in the general population.

“There is data suggesting that the COVID vaccine is associated with increased risk of thromboembolic events,” Linxin Li, another of the study’s co-authors, told Newsweek. “However, the absolute risk is very low and much lower than the stroke risk linked with COVID infection.”

Rothwell explained that the type of blood clot that has been linked to COVID-19 vaccinations is very different to the type typically seen in stroke patients.

“The COVID vaccine is associated with a small increase in absolute risk of blood clotting events, but these are of an unusual kind and are rather different to the more typical type of stroke that we see,” he said.

“COVID infection itself increases stroke risk much more–both during the illness and possibly in the longer-term if recent data published by others are to be believed.”

A large study, published in JAMA in July 2022, found that vaccinated individuals were less likely to experience strokes after infection with COVID-19 than those who were unvaccinated, suggesting that vaccination may actually reduce a patient’s stroke risk.

The Ruling

False.

The 2022 study provides no evidence that the COVID-19 vaccine is responsible for the increasing stroke rate in under 55s. The data used in this study was collected between 2002 and 2018 and therefore bears no relation to the COVID-19 pandemic.

While the vaccine has been associated with a small increase in blood clots, the absolute risk is much lower than the risk of blood clotting and stroke associated with COVID-19 infection. Therefore vaccination may reduce overall stroke risk for individuals exposed to SARS-CoV-2.

FACT CHECK BY NEWSWEEK