Seizures in vaccine leaflet relate to rare blood clots in brain

Callers to our Helpline have expressed concerns that the latest version of the patient information leaflet for the Covid-19 Astra Zeneca vaccine, mentions seizures as a possible side effect.

These seizures, however, are ‘symptom seizures’ which relate specifically to the rare cases of a blood clot as a side effect of the vaccine. Where a blood clot affects the brain, it may cause seizures. 

Professor Ley Sander, Medical Director at the Epilepsy Society, said: “There have been some extremely rare cases of blood clots occurring after the Astra Zeneca vaccine in people who have low numbers of blood platelets. If someone has a blood clot in the brain, they may experience a seizure as a result.

“This does not mean that the vaccine is likely to exacerbate seizures in people with epilepsy. This warning relates specifically to symptomatic seizures as a result of a blood clot.”

If you have any concerns about side effects following any of the Covid-19 vaccines, always seek medical advice.