The seizure mentioned in the risk sheet is caused by fever, i.e. a febrile seizure. Some children are susceptible to them and will get them when their temp goes up. They are not epileptic seizures. Stressful for parents but they can happen with any fever - due to a cold, teething, etc.
I meant to say last night that immunization can always be done; it's not an all or nothing decision. There are schedules for vaccination at any age. If anyone is interested in more information, I'd suggest the vaccine pages at
www.cdc.gov for a start.