Children are much more likely to suffer a seizure after an MMR (measles, mumps, rubella) vaccination if they have it later than the recommended 12 to 15 months. The risk rises nearly three-fold if the parents leave it until the child is between 16 and 23 months of age.
The usual seizure risk among children aged from 12 to 15 months is 2.65 times, but this rises to 6.53 times if the vaccination is delayed. The seizure risk is also higher among all age groups if the new four-in-one vaccine, the MMRV, which includes the rotavirus vaccine, is administered.
The increased seizure risk was identified by researchers from American's Centers for Disease Control and Prevention (CDC), after they analysed the records of 323,247 vaccinated children, and their health in the first two years of life. In all, 5,700 children suffered a seizure, and most were among older children.
(Source: Pediatrics, 2014; doi: 10.1542/peds.2013-3429)