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Influenza (Flu) in Children

What is the flu?

Influenza (flu) is a highly contagious viral infection of the respiratory system. It is one of the most severe common viral illnesses of the winter season. The flu has these common symptoms:

  • Fever

  • Muscle aches

  • Sore throat

  • Cough

The flu can make people of any age ill. Most people, including children, are ill with the flu for less than a week. But some children have a much more serious illness and may need to be treated in the hospital. The flu may also lead to pneumonia or death.

What are the different types of flu?

Flu viruses are divided into 3 types: A, B, and C.

  • Influenza types A and B cause epidemics of respiratory illness that happen almost every winter. They often lead to more people needing a hospital stay, and more people dying from the flu. Public health officials focus on stopping the spread of types A and B. One of the reasons the flu remains a problem is because the viruses change their structure often. 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.

Flu viruses continually change (mutate). This helps the virus to evade a child's immune system. Children (and adults) can get the flu no matter what their age. The process works like this:

  1. A child infected with a flu 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 child becomes infected again.

The older antibodies may 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 the flu?

A flu 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 the flu?

The flu 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 these 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 children recover from the flu within a week. But they still feel exhausted for as long as 3 to 4 weeks.

The symptoms of the flu may look like other health conditions. Make sure your child sees his or her healthcare provider for a diagnosis.

How is a cold different from the flu?

A cold and the flu are different illnesses. A cold is relatively harmless and usually clears up by itself after a period of time. Sometimes a cold may lead to another 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

How can the flu be prevented?

A new flu vaccine is available each year, before the start of flu season. All children, beginning at 6 months, should get the flu vaccine each year, as soon as it is available in their community. 

The flu vaccine is available as a shot. A nasal spray was also available but is not recommended for the 2016-2017 flu season. The CDC says this is because the nasal spray did not seem to protect against the flu over the last several flu seasons. In the past, it was meant for children ages 2 and older.

Your child's provider may prescribe antiviral medicines to help prevent your child from getting severe long-lasting symptoms or from getting the flu. Talk with your child's healthcare provider about antiviral medicines if your child was around someone with the flu.

You can also help prevent your child from getting the flu by following these tips:

  • When possible, have your child stay away from or limit contact with infected people.

  • Have your child wash his or her hands often. Frequent handwashing may reduce, but not eliminate, the risk for infection.

  • Have your child cover his or her nose and mouth with a tissue or inside elbow when coughing or sneezing to limit spread of the virus.

How well the vaccine works varies from year to year. It depends on how close the flu virus strains in the vaccine match the strain or strains that actually circulate during flu season. Vaccine strains must be chosen 9 to 10 months before the flu season. Sometimes changes occur in the circulating strains of viruses between the time vaccine strains are chosen and the next flu season. These changes may make it less likely for your child's antibodies to stop the newly mutated virus. This decreases the chance that the vaccine will work.

What are the side effects of the flu vaccine?

The most serious side effect of the flu vaccine is an allergic reaction in children who have a severe allergy to eggs. But, this is very rare. Vaccines are available for those with an egg allergy.

Some children who get the vaccine have soreness at the vaccine site. Some children have mild side effects, such as a headache or a low-grade fever for about a day after vaccine. Because these mild side effects are like some flu symptoms, some people believe influenza vaccine causes the flu. But this is not true.

What is currently recommended for children?

The vaccine is recommended for all children 6 months and older. Children who are allergic to eggs may get a different flu vaccine designed for people with an egg allergy. It is especially important that children in these groups get a flu shot: 

  • Children 6 months to 19 years old

  • Children of anyone  who has a chronic health condition

  • Children who have a long-term heart or lung condition

  • Children who have:

    • Endocrine disorders such as diabetes

    • Kidney or liver disorders

    • Weak immune system from diseases such as HIV or AIDS or taking long-term steroids

    • Blood disorders such as sickle cell disease

  • Children and teenagers ages 6 months to 19 years who are taking aspirin as long-term therapy

  • Children of people in high-risk groups

How is the flu treated?

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.

The goal of treatment is to help prevent or ease symptoms. Treatment may include:

  • Medicines such as acetaminophen or ibuprofen to relieve aches and fever. Don't give aspirin to children with a fever without talking to your child's healthcare provider first. The medicine of choice for children is acetaminophen.

  • Bed rest and more fluids

  • Medicine for your child's cough. These may be prescribed by your child's provider after a thorough checkup.

  • Antiviral medicines. These may help to shorten how long your child is ill and ease symptoms. But these medicines don't cure the flu. To work, they must be started within 2 days after symptoms begin. Your child's provider will let you know how long your child should take this medicine. The provider may also prescribe these medicines to help prevent the flu if your child is around someone who has it.

Online Medical Reviewer: Freeborn, Donna, PhD, CNM, FNP
Online Medical Reviewer: Lentnek, Arnold, MD
Date Last Reviewed: 10/1/2016
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