Majority of vaccine-induced seizures linked to underlying epilepsy syndromes

1. The majority of children (65%) diagnosed with new-onset epilepsy related to the administration of vaccinations were found to have an underlying genetic or structural neurological disorder which predisposed them to developing epilepsy. 

2. The etiologies for underlying epilepsy disorders unmasked by vaccination included: chromosomal deletions, neuronal migration disorders, Dravet Syndrome (severe myoclonic epilepsy of infancy), and familial febrile and infantile epilepsy disorders.

Evidence Rating Level: 2 (Good)  

Study Rundown: In recent years, increasing numbers of parents are refusing to vaccinate their children due to a fear of vaccine-induced neurologic syndromes. Previous research has shown that childhood vaccinations slightly increase the risk of febrile seizures, and these vaccinations are common precipitants for first seizures in children with underlying epilepsy disorders, such as Dravet Syndrome. This study focused on identifying and evaluating the underlying causes of seizures triggered by vaccinations. It was found that the majority of newly diagnosed epilepsy cases related to the administration of vaccines were explained by underlying genetic or structural disorders affecting the brain. These included Dravet Syndrome, generalized epilepsy with febrile seizures plus syndrome, chromosomal microdeletions, neuronal migration disorders, and other familial epilepsy syndromes. Results may be limited as the proportion of participants with benign epilepsy could potentially be underestimated due to the narrow follow-up period. This study may aid physicians in counseling vaccination-resistant parents as well as encourage genetic testing in children with vaccination-related seizures.

Click to read the study, published today in Pediatrics

Relevant Reading: The risk of seizures after receipt of whole-cell pertussis or measles, mumps, and rubella vaccine

Study Author, Nienke E. Verbeek, MD, MSc, talks to 2 Minute Medicine: Department of Medical Genetics, Division of Biomedical Genetics, University Medical Centre Utrecht.

“Our study shows that in the majority of children with onset of epilepsy after vaccination, genetic or structural causes of the epilepsy can be identified. Physicians should discuss with the parents that, although vaccinations appear to be the cause of the epilepsy, they most likely only have unmasked a genetic seizure predisposition in their child by acting as a trigger for the first seizure. Furthermore, physicians should consider genetic testing in children with epilepsy onset related to vaccination, in an early stage. Knowledge of the underlying cause of the epilepsy could help to identify appropriate treatment options, genetic counseling may be provided, and it may even support faith in vaccination programs.”

In-Depth [retrospective cohort study]: Data was gathered from the National Institute for Public Health and Environment in the Netherlands. Participants included 990 children, ages 0 to 2 years, with vaccination-related seizures from 1997 to 2006. Vaccination-related seizures were defined as seizures occurring within 24 hours after administration of an inactivated vaccine or between 5 to 12 days after a live attenuated vaccine. True vaccination-related onset of epilepsy was identified in 26 children, 23 of whom underwent further follow-up. Underlying causes for epilepsy were found in 65% of these cases. Preexisting encephalopathy with developmental delay due to chromosomal and neuronal migration disorders was found in 13% of the 23 children. Epileptic encephalopathy was triggered by vaccination in 52% of children, and 83% of these cases were due to an underlying genetic (e.g. Dravet Syndrome) or structural disorder. A benign and controllable epilepsy was seen in 35% of children. A genetic history of epilepsy was identified in 38% of the benign cases (family history of febrile seizures, unclassified familial epilepsy, and familial infantile epilepsy).

More from this author: Preterm birth associated with cardiovascular risk factors in adolescence,  Parental conceptions of weight are becoming increasingly inaccurate, Vitamin K refusal for newborns linked to non-immunization, Amount of electronic gameplay associated with psychosocial adjustment, Impaired brain growth in preterm infants linked with delayed cognitive development

Image: PD 

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