Abstracts

Rationale: Berkovic et al. (Lancet Neurol. 2006) reported about mutations in the SCN1A gen in 11 out of 14 children with alleged vaccine encephalopathy. Fever and afebrile infections but also vaccinations can characteristically provoke seizures in children with SCN1A-mutations and severe myoclonic epilepsy of infancy. Against this background resulted the following questions for our research work on vaccine-associated seizure-provocation in children with SCN1A-mutation: (i) What is the reported frequency of vaccine-associated seizures, (ii) after what type of immunization do they occur and (iii) with what temporal interval to the vaccination. Methods: We analyzed the data of 70 patients (aged 2-22 years) with proven SCN1A-mutations regarding the possible provocation of seizures caused by vaccination according to (i) the kind the vaccination (ii) children’s age at vaccination (iii) interval between vaccination and seizures (iv) fever association as well as (v) effect on further immunization modalities. Results: Parents of 24 (34%) patients (aged 2-18 years) reported on the provocation of seizures caused by vaccination at childrens age from 4 months to 7 years. Only 12 (50%) of the mentioned patients had seizures associated with fever. In 13 cases (54%) parents reported that epilepsy started with a seizure which was supposed to be provoked by vaccination. The reported interval between vaccination and seizure varied from 2 hours to 23 days, whereas 71 % occurred during 72 hours after application of vaccine. 35 of 45 (78%) of the reported seizures succeded after a combined immunization with diphtheria/ pertussis/tetanus vaccine (also in additional combinations). In 8 cases (18%) seizures occurred after measles/mumps/rubella immunization, but also after influenza (2%) and pneumococcus vaccination (2%). Conclusions: Parents reported a provocation of seizures caused by vaccination within 34% of our patients with SCN1A-Mutation - often these seizures had no sign of accompanying fever. While a causal relationship is very unlikely in cases more than 3 days have passed after vaccination, it can’t be excluded. In case of seizures after vaccination in combination with other clinical features SCN1A-mutation has to be considered. There is no evidence on causally correlation.