Febrile convulsions after vaccination

Between 2 and 5 per cent of children have experienced febrile convulsions by the age of seven.

The susceptibility to them is genetic. A simple febrile convulsion will usually last for a short time (1–2 min) or up to 15 min. During the seizure, the feet or hands, or both, jerk or stiffen symmetrically on both sides. Some of the children only go limp and have no convulsions. 

Febrile convulsions occurring after vaccinations are rare

Febrile convulsions occur rarely in little children after a combination vaccine. They have been reported mainly in connection with MMR vaccinations. For example, the likelihood of febrile convulsions is considerably higher in a person with measles than among those who have been given an MMR vaccine.

Do not confuse a febrile convulsion with an epileptic seizure. Fever may not have been detected before convulsions, and the convulsions may be the first sign of fever. 

Jerky movements resembling a convulsion can occur if a person faints after a vaccination. These are harmless and usually quick to disappear, and should not be confused with a febrile or some other type of convulsion.

Treating febrile convulsion

A convulsive attack occurring after vaccination is treated similarly as any type of a seizure.

  • If this is your child’s first febrile convulsion, contact your doctor or emergency clinic.
  • Treat high fever effectively. Give a sufficient dose of antipyretic medication and reduce the clothing of the vaccinated person.
  • Prevent the child from harming him/herself during convulsions. Make sure that the child's breathing is unobstructed.
  • If you have medication used to treat the child’s previous febrile convulsions at home, give that to the child.
  • If the convulsions continue for more than 5 minutes after you have given the child the convulsion medication, contact your doctor or the emergency clinic. 
  • If the child is confused, vomiting, has pain or otherwise abnormal after the convulsion, consult your doctor or emergency clinic. 
  • Send the child to hospital monitoring if the convulsions are not alleviated by first aid medication, if they are asymmetrical or if repeated convulsions occur during the same bout of fever.

Follow-up vaccinations after febrile convulsion

Follow-up vaccinations can be given as normal if the vaccine recipient is neurologically asymptomatic. 

Further examinations are not necessary if the child (aged 6 months to 6 years) only has simple attacks of unconsciousness and febrile convulsions, from which the child recovers normally. 

Children who have experienced febrile convulsions after vaccination have not been found to have recurring convulsive attacks or other consequences. Fever convulsions cause no harm to the child's later development and do not indicate epilepsy. 

Afebrile convulsions occur very rarely after vaccinations.