Children's Health

Childhood immunizations can reduce the risk for fever-related illnesses, such as Haemophilus influenzae type b (Hib) infection. Although no vaccine is 100% effective, most routine childhood immunizations are effective for 85% to 95% of the children who receive them. For more information, see the topic Immunizations.

Causes of fever

It is not unusual for a preschool-aged child to have 7 to 10 viral infections in a year. Each new viral infection may cause a fever. It may seem that a fever is ongoing, but if 48 hours pass between fevers, then the new fever is most likely from a new illness.

Common causes of fever include:

• Viral infections, such as colds, flu, and chickenpox.
• Bacterial infections, such as a urinary tract infection.
• Immunizations.

Teething does not cause a fever. If a baby is teething and has a fever, look for other symptoms that may need to be evaluated.

A fever that increases quickly may lead to a fever seizure in some children. After a fever has reached a high temperature, the risk of a seizure is less. Fever seizures can be frightening to see, but they usually do not cause other problems, such as brain damage, intellectual disability, or learning problems. If your child has a high fever and a seizure, see the topic Fever Seizures.

Check your child's symptoms to decide if and when your child should see a doctor.