Dr Lucy Deng

Febrile seizures following vaccination have no adverse effect on a child’s developmental and behavioural outcomes, Australian research has shown

Dr Lucy Deng and colleagues at the National Centre for Immunisation Research and Surveillance (NCIRS) in Sydney investigated cognitive outcomes in 62 children who had a fever-associated seizure within two weeks of a vaccination with 70 children who had a fever-associated seizure from another cause and 90 children without a history of seizures.

The children who had seizures were younger than 2.5 years old at the time of the seizure, and were treated  at one of four tertiary paediatric hospitals between May 2013 and April 2016.

The children’s development was assessed at 12 to 24 months after their initial febrile seizure and at aged 12 to 42 months for control children using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III).

Childrens’ behaviour and executive functioning was assessed using the preschool version of the Behaviour Rating Inventory of Executive Function and the Child Behaviour Checklist, preschool.

The study found no significant differences in cognitive function between children with vaccination-proximate febrile seizures and those with non-vaccine febrile seizures or those in the control group

There were no significant differences for any other developmental measures or any borderline or significant developmental impairment compared with controls. There also were no clinically significant behavioural differences between any of the groups.

The researchers noted that several other factors were not associated with having developmental problems: fever-associated seizures before the age of one; a febrile seizure lasting for more than 15 minutes; or more fever-associated seizures after the first seizure

The only predictor of cognitive functioning in children with any kind of seizure was maternal education or socioeconomic status .

“This is reassuring news for parents,” said Dr Deng.

“A febrile seizure can occur following vaccination and understandably can be quite distressing to parents. It can also cause parents to lose confidence in future vaccinations. Now, parents will be relieved to hear that having a febrile seizure following vaccination does not affect the child’s development.”

“At a time when there is a global resurgence of measles and new diseases are emerging, our findings are particularly important in reassuring parents and providers on the safety of vaccines,” she added.

The new study is published in Neurology.