People have been worried about whether vaccinations can cause epilepsy for about fifty years. The vaccine that has caused the most concern has been that for pertussis, or whooping cough. Professor Simon Shorvon, of the Institute of Neurology, University College London, described these issues in an article published in
December 2007 in the journal Epilepsia.

The first concern is that developing a high temperature after a vaccination can trigger a febrile seizure in a child who is prone to them. Children who have febrile seizures have a higher risk of developing epilepsy when they're older than children who don't. High temperatures happen particularly after the combined measles, mumps and rubella (MMR) vaccine and after the combined diphtheria, tetanus and whooping cough (DTP) vaccine.

The second fear is that the vaccine directly causes a condition called an epileptic encephalopathy, where seizures damage the brain and this damage leads on to more seizures, and so on. These are very serious conditions. A very small number of encephalopathy cases have been linked to whooping cough vaccinations, but there is no consensus that "pertussis vaccine encephalopathy" really exists.

Recent research studies into whooping cough vaccinations and the risk of epilepsy have all come to the same conclusion. The risk of a febrile seizure after a vaccination is extremely low, or about 1 in 20,000 children. The risk of a seizure that's not due to a temperature after a vaccination is even lower, at about 1 in every 75,000 children. Finally, the risk of an encephalopathy is between 0 and 3 in a million children.

These numbers are so low it's difficult to prove that there really is a link between the vaccination and the encephalopathy. Having a family history of epilepsy or febrile seizures, or having epilepsy itself, is therefore not a reason to avoid being vaccinated.

In 2006, a study of 14 cases of "pertussis vaccine encephalopathy" found that 11 out of the 14 children concerned had a genetic mutation (SNC1A, controlling sodium channels in brain cells) which was instead responsible for their epilepsy. This study thus provided a solid alternative explanation for these cases. This raises the possibility that all previously identified cases of vaccine-induced encephalopathies might in fact have a genetic basis.

Understanding that whooping cough vaccination poses a very low risk of causing epilepsy is important, so as to encourage as many people as possible to take up the vaccine for their children.

Download Epilepsy Research UK's free information leaflet
about vaccinations for people with epilepsy here (, 41KB)