Influenza (Flu) in Children

What is influenza?

Influenza (flu) is a highly contagious viral infection and is one of the most severe illnesses of the winter season.

Influenza is a viral infection of the upper respiratory system, which includes the nose, bronchial tubes, and lungs. Influenza has these common symptoms:

  • Fever
  • Muscle aches
  • Sore throat
  • Nonproductive cough

Influenza can make people of any age ill. Although most people, including children, are ill with influenza for less than a week, some have a much more serious illness and may need to be hospitalized. Influenza may also lead to pneumonia or death.

What are the different types of influenza?

Influenza viruses are divided into three types designated as A, B, and C:

  • Influenza types A and B cause epidemics of respiratory illness that happen almost every winter. They often lead to increased rates of hospitalization and death. Public health efforts to control the impact of influenza focus on types A and B. One of the reasons the flu remains a problem is because the viruses actually change their structure regularly. This means that people are exposed to new types of the virus each year.
  • Influenza type C usually causes either a very mild respiratory illness or no symptoms at all. It does not cause epidemics and does not have the severe public health impact that influenza types A and B do.

Influenza viruses continually change (mutate), which helps the virus to evade the immune system of both children and adults. People can get the flu no matter what their age. The process works like this:

  1. A person infected with an influenza virus develops antibodies against that virus.
  2. The virus changes.
  3. The "older" antibodies no longer recognize the "newer" virus when the next flu season comes around.
  4. The person becomes infected again.

The older antibodies can give some protection against getting the flu again. Vaccines given each year to protect against the flu contain the influenza virus strain from each type that is expected to cause the flu that year.

What causes influenza?

An influenza virus is generally passed from person to person through the air. This means your child can get the flu by coming in contact with an infected person who sneezes or coughs. The virus can also live for a short time on things like doorknobs, pens or pencils, keyboards, telephone receivers, and eating or drinking utensils. So your child can get the flu virus by touching something that has been handled by someone infected with the virus and then touching his or her own mouth, nose, or eyes.

People are generally the most contagious with the flu 24 hours before they start having symptoms and during the time they have the most symptoms. That's why it is hard to prevent the spread of the flu, especially among children, because they do not always know they are sick while they are still spreading the disease. The risk of infecting others usually stops around the seventh day of the infection.

What are the symptoms of influenza?

Influenza is called a respiratory disease, but the whole body seems to suffer when a child has it. Children usually become suddenly ill with any or all of the following symptoms:

  • Fever, which may be as high as 103° F (39.4° C) to 105° F (40.5° C)
  • Muscle and joint aches and pains
  • Not feeling well "all over"
  • Headache
  • Sore throat
  • Runny or stuffy nose
  • Worsening cough
  • Nausea
  • Vomiting
  • Diarrhea
  • Fatigue

Most people recover from influenza within a week, but they still feel exhausted for as long as 3 to 4 weeks.

The symptoms of influenza may resemble other conditions or medical problems. Always see your child's healthcare provider for a diagnosis.

How is a cold different from the flu?

A cold and the flu are two different illnesses. A cold is relatively harmless and usually clears up by itself after a period of time. Sometimes a cold may lead to a secondary infection, such as an ear infection. But the flu can lead to complications, such as pneumonia and even death. What may seem like a cold may be the flu. Be aware of these differences:

Cold symptoms

Flu symptoms

Low or no fever

High fever

Sometimes a headache

Headache (very common)

Stuffy, runny nose

Clear nose or stuffy nose


Sometimes sneezing

Mild, hacking cough

Cough, often becoming severe

Slight aches and pains

Often severe aches and pains

Mild fatigue

Several weeks of fatigue

Sore throat

Sometimes a sore throat

Normal energy level or may feel sluggish

Extreme exhaustion

About the influenza vaccine

The Centers for Disease Control and Prevention (CDC) recommends that everyone 6 months of age and older receive the influenza vaccine each year.

Children 6 months to 8 years of age require two doses of influenza vaccine separated by four weeks if they:

  • Have never received an influenza vaccine
  • Have not received at least 1 dose of influenza vaccine last year (2013-14 influenza season) or have not received two doses of influenza vaccine since July 2010
  • Have an uncertain influenza vaccination history

Visit the Vaccine Education Center to learn more about influenza and the influenza vaccine.

What is the treatment for influenza?

Specific treatment for influenza will be determined by your child's doctor based on:

  • Your child's age, overall health, and medical history
  • The severity of symptoms
  • Your child's tolerance for specific medications, procedures, or therapies
  • Expectations for the course of the condition
  • Your opinion or preference

The goal of treatment for influenza is to help prevent or decrease the severity of symptoms. Treatment may include:

  • Medications, such as acetaminophen or ibuprofen, to relieve aches and fever. Aspirin should not be given to children with a fever without talking to your child's healthcare provider first. The drug of choice for children is acetaminophen.
  • Bed rest
  • Increased fluid intake
  • Medication for your child's cough may be prescribed by your child's provider after a thorough check-up.
  • For anyone in a high-risk group, it’s important that the flu is identified and treated early, to avoid complications.

About flu testing

How does CHOP test for the flu?

Beginning in the 2018-2019 flu season, we will be using a rapid flu test called a “rapid molecular assay” that detects the genetic material of the virus from a nasal swab within 15 minutes. This test can help clinicians decide whether antiviral treatment is necessary for certain high-risk patients.

Who will be tested for the flu?

Only high-risk patients will be tested.

Who is considered high-risk?

  • Children younger than 5 years old (especially those younger than 2) and those older than 65
  • People diagnosed with:
    • Certain respiratory diseases such as asthma
    • Neurological and neurodevelopmental conditions such as seizure disorders
    • Heart disease
    • Disorders of the blood, endocrine system, kidneys, liver or the metabolic system
    • Those with weakened immune systems
    • People younger than 19 years of age who are receiving long-term aspirin therapy
    • People with extreme obesity
    • People with household members who have compromised immune systems, such as family members with cancer who are receiving chemotherapy

What is the treatment if a high-risk patient has the flu?

Antiviral drugs may make illness milder and shorten the time someone is sick. They may also prevent serious flu
complications, like pneumonia.

Studies show that flu antiviral drugs work best for treatments when they are started within two days of getting sick.

As with all medicines, some side effects have been associated with the use of flu antiviral drugs, including nausea, vomiting, dizziness, runny or stuffy nose, cough, diarrhea, headache, and some behavioral side effects.

Your clinician will use all of these factors to decide if your child will benefit from rapid flu testing and treatment.

What is the cost of the flu test?

Your insurance company will be billed for the testing, but different insurers vary in whether or not they will cover (or partially cover) the cost of the test. Deductibles, copays and coinsurance may apply. Contact your insurance company to determine if you will be charged an additional fee for testing.

Next Steps
Contact Us (1-800-TRY-CHOP)