What is the frequency of seizures following MMR, if any?
MMR vaccination, like other causes of fever, may trigger febrile seizures. The risk for such seizures is approximately 1 case per 3,000 doses of MMR vaccine administered. Studies have not established an association between MMR vaccination and residual seizure disorders. Although children with a personal or family history of seizures are at increased risk for idiopathic epilepsy, febrile seizures after vaccinations do not increase the probability that epilepsy or other neurologic disorders will subsequently develop in these children. Most convulsions that occur after measles vaccination are simple febrile seizures, which affect children who do not have other known risk factors for seizure disorders.
