MALMO, SWEDEN – Children who experience a febrile seizure in conjunction with a vaccination have developmental outcomes comparable with those of children who have non–vaccine-related febrile seizures and healthy controls who’ve never had a febrile seizure, according to the first prospective case-control cohort study to examine the issue.
This finding has important implications for clinical practice, Lucy Deng, MD, observed at the annual meeting of the European Society for Paediatric Infectious Diseases.
“Febrile seizures associated with a vaccine can decrease parent and provider confidence in vaccine safety,” the pediatrician noted. Based upon her study results, however, physicians now can offer a truly evidence-based message of reassurance.
“If you have a child with a vaccine-related febrile seizure, you can give the same advice to those parents as for anyone else who’s had a febrile seizure, in that there is no difference in the clinical outcomes of vaccine-proximate and non–vaccine-proximate febrile seizures. Vaccine-proximate febrile seizures are usually brief, they don’t require any antiepileptic drugs, their length of stay is usually less than a day, and developmentally at 12-24 months post initial febrile seizure, they’re exactly the same as children who’ve never had a seizure before or who’ve had a non-vaccine-related febrile seizure,” said Dr. Deng of the National Centre for Immunisation Research and Surveillance in Sydney.
The impetus for her study was straightforward: “We all know that most children with a history of febrile seizures have normal behavior, intelligence, and academic achievement and do not later develop epilepsy. What we didn’t know before is if all of these facts apply to vaccine-proximate febrile seizures,” she explained.
The clinical severity analysis portion of this prospective case-control cohort study included 1,085 children with febrile seizures seen at five Australian children’s hospitals. Sixty-eight of them had vaccine-proximate febrile seizures, for a 6.6% rate. The febrile seizures in the other 1,027 children didn’t occur within 2 weeks following a vaccination.
Measles vaccine was implicated in 56 of the 68 children with vaccine-proximate febrile seizures, or 82%. Because Australian children receive their first measles-containing vaccine at age 12 months, the average age of the cohort with vaccine-proximate febrile seizures was 13 months, significantly younger than the 20-month average for children with non–vaccine-related febrile seizures.