The occurrence of seizures related to fever results from complex interactions among genetic and environmental factors. The issue of the relationship between vaccination and febrile seizures is complex. It is difficult to identify whether the febrile seizures result from a nonspecific fever caused by vaccination or if these are secondary to an encephalitis or encephalopathy caused by the vaccine. There is evidence showing that vaccination does trigger the onset of febrile seizures in one third of patients with Dravet syndrome. In general, febrile seizures that occur after vaccination do not seem to be different from febrile seizures from other causes, thus advances in knowledge about febrile seizures in general should be relevant to vaccine-associated febrile seizures.52 Suppl 323-5