MMR vaccination nearly triples the risk of febrile seizures within two weeks of vaccination, and some children are genetically vulnerable to this serious MMR-related adverse event.
Common variants associated with general and MMR vaccine-related febrile seizures
Feenstra B, Pasternak B, Geller F, et al. Nature Genetics 2014;46(12):1274-1282.
MMR vaccination nearly triples the risk of febrile seizures—a serious adverse event—within two weeks of vaccination. This study explored whether genetic variants might explain the increased risk by comparing children who experienced MMR-related febrile seizures to children who had “MMR-unrelated febrile seizures” as well as a control group free of seizures. The analysis identified two genetic loci “distinctly associated with febrile seizures as an adverse event following MMR vaccination”—and four more related to febrile seizures in general. The authors hypothesize a two-stage response whereby the MMR-related genetic variants induce fever and then the febrile seizure variants trigger the seizure response. They note the need for additional studies “to determine whether the variants are associated with response to other vaccines.”