Risk of febrile seizures associated with the Measles-Mumps-Rubella-Varicella Combination Vaccine (MMRV): data from spontaneous

In previous studies, associations between Measles-Mumps-Rubella Combination Vaccine (MMR) and increased risk for febrile seizures 1 to 2 weeks after vaccination were observed. Aim of this study is it analyze the data on febrile seizures by MMR, MMRV and varicella (VAR) in the Italian spontaneous reporting database. Cases has been defined as reports with the WHO-ART terms “Fever convulsions” or “Febrile seizures” or reports including both any term related to seizures (eg “Convulsions” or “convulsions neonatal”) and any term related to fever (eg fever neonatal or hyperpyrexia). Our results are in line with other published studies suggesting an increased risk of febrile seizures for the combined MMRV compared to a separate administration of MMR and VAR. However due to the limitations of spontaneous reporting further studies are needed to confirm this signal.