One in 20 children will have at least one seizure during their childhood. A single seizure does not mean a child has epilepsy. Febrile convulsions are not considered epilepsy. Epilepsy is a disorder of the brain that leads to a person having repeated unprovoked seizures. About one in 200 children has epilepsy.

Vaccine-proximate seizures

Seizures occurring within 14 days of a vaccine are defined as vaccine-proximate (VPS). Most children with epilepsy do not have a high risk of VPS. However, there are some genetic epilepsies with a strong association with VPS. These include Dravet syndrome and genetic epilepsy with febrile seizures plus (GEFS+).

Dravet syndrome

Dravet syndrome is a rare and severe form of infantile onset epilepsy with a prevalence of 1 in 15,500 – 40,000 children. Children with Dravet syndrome classically present in the first year of life with prolonged febrile seizures. These seizures can be hemiclonic (one-sided) or generalised tonic-clonic seizures and sustained such as in status epilepticus (SES). Their first seizure may be associated with their primary series of immunisation, often their 4 or 6 month vaccines. They then develop refractory (uncontrolled) afebrile seizures, particularly myoclonic seizures, and a plateau or regression in their development. A genetic mutation, usually as a one-off (de novo) change in the sodium channel gene SCN1A is found in approximately 80% of children with Dravet syndrome. VPS in infants, particularly if prolonged or SES, should raise suspicion of Dravet syndrome.  The first seizure is vaccine-proximate in approximately 30% of children with Dravet syndrome. Immunisation can lead to an earlier age of seizure onset in children with Dravet syndrome. However there is no difference in developmental or seizure outcomes in children who had a first seizure proximate to immunisation compared to children with seizures unrelated to immunisation.

Genetic epilepsy with febrile seizures (GEFS+)

Genetic epilepsy with febrile seizures plus (GEFS+) is a spectrum of seizure disorders of varying severity. A diagnosis of GEFS+ is usually made in individuals whose family members have febrile seizures with or without recurrent afebrile seizures (epilepsy).  Some children with GEFS+ have VPS.

Immunisations in Dravet syndrome and other children at risk of vaccine-proximate seizures

There is a well-reported association between febrile seizures/SES and immunisations in children with Dravet syndrome and some other genetic epilepsies, especially within the first 48 hours following an inactivated vaccine. Live-attenuated vaccines may also cause seizures 5-10 days post vaccination, often post the measles-mumps-rubella (MMR) vaccine given at 12 months.

The decision to immunise children with Dravet syndrome or other children with VPS requires a comprehensive discussion between the patient’s family and the treating medical teams, usually both immunisation experts and neurologists. Immunisations provide protection from common, and sometimes devastating, childhood vaccine preventable diseases, such as influenza, which can cause significant harm as well as also triggering febrile seizures/SES. Thus, it is in the child’s best interests to be fully vaccinated with a clear plan by the medical team to ensure safe re-vaccination under careful medical supervision if possible.

Prevention of vaccine-proximate seizures

There is no published data evaluating prophylactic measures to prevent seizures in children with Dravet syndrome undergoing immunisations. There is anecdotal evidence and experience that prophylactically administering antipyretics and benzodiazepines to children with Dravet syndrome prior to and after immunisation can reduce the rate of immunisation-related seizures and SES.

Management

If your child/patient has a diagnosis, or suspected diagnosis, of Dravet syndrome or other genetic epilepsy, they should be referred to a Specialist Immunisation Clinic for review as well as being seen by a neurologist. A clear plan for re-vaccination can be discussed, including consideration for admission to hospital under the Protocol for immunisation of children with Dravet syndrome or other vaccine-proximate seizures.

Children with epilepsy who have not had previous VPS and whose type of epilepsy is not strongly associated with VPS generally do not require prophylactic treatment around the time of vaccination. However, where there are questions or concerns about safety of vaccination in an individual child, referral to a Specialist Immunisation Clinic could be considered.

Key message

Protection from vaccine preventable diseases is important in children with epilepsy and a clear plan should be discussed and developed with the medical team and parents to ensure that the child’s routine immunisations are completed if possible. In children who have had previous vaccine-proximate SES or those with a high risk of having vaccine-proximate SES (e.g. Dravet syndrome), strong consideration should be given to performing future vaccinations under careful medical supervision in a hospital, in close collaboration with the treating neurologists.

Resources:

Authors: Georgina Lewis (Clinical Manager, SAEFVIC, Murdoch Children’s Research Institute), Nigel Crawford (Director, SAEFVIC, Murdoch Children’s Research Institute), Margie Danchin (Paediatrician, Murdoch Children’s Research Institute and Royal Children’s Hospital) and Gabriel Dabscheck and Katherine Howell (Royal Children’s Hospital neurologists)

Date: March 2020

Materials in this section are updated as new information and vaccines become available. The Melbourne Vaccine Education Centre (MVEC) staff regularly reviews materials for accuracy.

You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family’s personal health. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult a healthcare professional.