If your child had a febrile seizure after vaccination, gets high fevers after shots, or has a history of febrile seizures, get clear, evidence-based information about vaccine-related fever, which vaccines may slightly raise risk, and when to call your child’s clinician.
About this assessment
Share whether your concern is a febrile seizure after immunization, fever after vaccines, MMR vaccine febrile seizure risk, flu shot questions, or worries about future vaccines after a prior seizure.
Sometimes, but the risk is generally low. Febrile seizures are triggered by fever, not by the vaccine itself causing epilepsy or a long-term seizure disorder. Some vaccines can cause fever as part of the normal immune response, and in a small number of children that fever may trigger a febrile seizure. This is why parents often search for answers about vaccines and febrile seizures in children. The key questions are which vaccine was given, when the fever started, your child’s age, whether your child has had febrile seizures before, and whether there are any signs of a more serious illness.
The MMR vaccine febrile seizure risk is small but known, usually during the period when fever can develop several days after vaccination. MMRV may carry a slightly higher febrile seizure risk than giving MMR and varicella separately in some age groups.
Parents often ask, does the flu shot cause febrile seizures? The flu shot alone has a low risk, but fever-related seizure risk may be slightly higher in some young children when influenza vaccine is given at the same visit as certain other vaccines.
Some routine vaccines can cause fever in the day or two after immunization, and that fever after vaccines may rarely lead to a febrile seizure in a child who is susceptible. Your child’s age, vaccine timing, and seizure history matter when estimating risk.
A febrile seizure after vaccination is more likely to be related if it happens during the expected fever window for that vaccine. Seizures that happen outside that window may point to a viral illness or another cause.
How high the fever was, how quickly it rose, and whether your child had other symptoms can help explain whether this was a typical fever after vaccines febrile seizure or something that needs urgent evaluation.
Children with a personal or family history of febrile seizures may be more likely to have another one with any fever, including fever after immunization. That does not automatically mean vaccines should be delayed or avoided.
If your child had a vaccine side effects febrile seizure event, contact your child’s clinician to review the vaccine given, the timing, the fever, and whether any follow-up is needed. Seek urgent care right away if the seizure lasts more than 5 minutes, your child has trouble breathing, does not return to normal, has a stiff neck, severe lethargy, repeated vomiting, or you are worried something more serious is going on. For future vaccines, many children can still stay on schedule, but the plan may depend on age, prior seizure history, and which vaccine was involved.
Understand how common febrile seizures after vaccines are, which vaccines may raise risk slightly, and whether your child’s episode fits the usual pattern.
Get practical guidance for discussing timing, vaccine combinations, fever expectations, and follow-up questions with your child’s clinician.
Learn which symptoms fit a typical febrile seizure after immunization and which signs mean your child should be evaluated promptly.
They are uncommon. Some vaccines are associated with a small increased risk during the period when fever may occur, but most children do not have a febrile seizure after vaccination.
The flu shot alone has a low risk. In some young children, risk may be slightly higher when influenza vaccine is given at the same visit as certain other vaccines, but febrile seizures after the flu shot are still uncommon overall.
MMR is known to have a small increased febrile seizure risk during the days when vaccine-related fever can occur. The overall risk remains low, and the protection from vaccination is important.
Not necessarily. Many children can continue routine vaccines, but the decision should be reviewed with your child’s clinician based on the vaccine involved, your child’s age, seizure history, and any other medical concerns.
Vaccines that can cause fever may rarely trigger a febrile seizure in a susceptible child. The best-known examples include MMR, MMRV, and in some situations influenza vaccine given with certain other vaccines.
Personalized assessment
Answer a few questions about your child’s seizure history, vaccine timing, and fever pattern to get clear next-step guidance you can use when talking with your child’s clinician.