Influenza (Flu) in Children

What is the flu in children?

Influenza (flu) is a very contagious viral infection that affects the air passages of the lungs. It causes a high fever, body aches, a cough, and other symptoms. It's one of the most severe and common viral illnesses of the winter season. Most children are ill with the flu for less than a week. But some children have a more serious illness and may need to be treated in the hospital. The flu may also lead to lung infection (pneumonia) or death.

What causes the flu in a child?

The flu is caused by flu viruses. Flu viruses are divided into 3 types:

  • Influenza types A and B. These 2 types of viruses cause widespread illness (epidemics) almost every winter. They often lead to more people needing to go to the hospital, 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 (mutate) often. This means that people are exposed to new types of the viruses each year.

  • Influenza type C. This type of virus causes a very mild respiratory illness. It rarely causes epidemics. It does not have the severe public health impact that influenza types A and B do.

A flu virus is often passed from child to child through sneezing or coughing. The virus can also live for a short time on surfaces. This includes doorknobs, toys, pens or pencils, keyboards, phones and tablets, and counter tops. It can also be passed through shared eating utensils and drinking. Your child can get a flu virus by touching something that was touched by an infected person, and then touching his or her mouth, nose, or eyes.

People are most contagious with the flu 24 hours before symptoms start, and while symptoms are most active. The risk of infecting others usually ends around day 7 of the illness. Because the flu can be spread before symptoms start, it’s easy to pick up a flu virus. This is true especially with children, who often touch many surfaces and then their mouth, nose, or eyes.

Which children are at risk for the flu?

A child is more at risk for the flu if he or she:

  • Is around people infected with the flu

  • Has not had the flu vaccine

  • Does not wash his or her hands after touching infected surfaces

Young children and children with certain underlying health conditions are at increased risk for a hospital stay or severe or complicated influenza infection. 

What are the symptoms of the flu in a child?

The flu is a respiratory disease, but it can affect the whole body. A child can 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)

  • Body aches, which may be severe

  • Headache

  • Sore throat

  • Cough that gets worse

  • Tiredness

  • Runny or stuffy nose

In some cases, your child may also have symptoms such as:

  • Nausea

  • Vomiting

  • Diarrhea

Most children recover from the flu within a week. But they may still feel very tired for as long as 3 to 4 weeks.

It’s important to note that a cold and the flu have different symptoms:

Cold symptoms

Flu symptoms

Low or no fever

High fever

Sometimes a headache

Headache in most cases

Stuffy, runny nose

Clear nose, or stuffy nose in some cases


Sneezing in some cases

Mild, hacking cough

Cough, often turning severe

Mild body aches

Severe body aches

Mild tiredness

Extreme tiredness that can last weeks

Sore throat

Sore throat in some cases

A cold is usually mild and often goes away after a few days. The flu can cause severe symptoms and lead to problems such as pneumonia and even death. The symptoms of the flu can be like other health conditions. Make sure your child sees his or her healthcare provider for a diagnosis.

How is the flu diagnosed in a child?

The healthcare provider will ask about your child’s symptoms and health history. He or she will give your child a physical exam. The symptoms are often enough to diagnose the flu. Your child’s provider may do other tests, depending on your child’s symptoms and overall health. 

How is the flu treated in a child?

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. This is to help lessen body aches and fever. Don't give aspirin to a child with a fever.

  • Antiviral medicine. This may help to ease symptoms, and shorten the length of illness. This medicine does not cure the flu. The medicine must be started within 2 days after symptoms start.

Antibiotics aren’t effective against viral infections, so they are not prescribed. They may be used, though, if your child has developed bacterial pneumonia. Otherwise, treatment focuses on helping ease your child’s symptoms until the illness passes.

Talk with your healthcare providers about the risks, benefits, and possible side effects of all medicines.

Also make sure your child:

  • Gets lots of rest in bed

  • Drinks plenty of fluids

What are possible complications of the flu in a child?

The flu can cause severe breathing problems. A child with severe symptoms may need to stay in the hospital. The flu can lead to a lung infection called pneumonia. In some cases, the flu can lead to death.

Children who have other health conditions that affect breathing, like asthma, are at greater risk for flu complications.

How can I help prevent the flu in my child?

The best way to prevent flu is to have the yearly flu vaccine. Each year, a new flu vaccine is available before the start of the flu season. For the 2019-2020 influenza season, flu shots and nasal spray are available. Talk with your healthcare provider if you have questions about how vaccines work and how well they prevent flu.

The flu vaccine is most often given as a shot into the muscle. For babies and young children, it's given as a shot in the thigh muscle. In older children, it's given as a shot in the upper arm muscle. It's also available as a nasal spray for healthy children over the age of 2, including teens who are not pregnant. Check with your child’s healthcare provider to see which is the best choice for your child.

The first time a child between the ages of 6 months and 8 years gets a flu vaccine, he or she will need a second flu vaccine 1 month later. This is to build up protection against the flu. Get your child’s first dose as soon as the vaccine is available to allow the second dose to be given by the end of October. This will give your child the best protection for the flu season. After the first flu season, your child will need only 1 dose.

The vaccine is advised for all children 6 months and older. But for some children, it’s more critical for them to get a flu shot because they are more likely to have complications from the flu. The flu shot should be given to any child who has any of these:

  • A long-term heart or lung condition

  • An endocrine disorder such as diabetes

  • A kidney or liver disorder

  • Weak immune system from HIV/AIDS or long-term steroids

  • A blood disorder such as sickle cell disease

A flu shot should also be given to: 

  • A child who has a family member with a chronic health condition

  • A child or teen taking aspirin as long-term therapy

  • A child with parents or caregivers at high risk of complications from the flu

Some side effects of the vaccine can be like mild flu symptoms, but the vaccine does not cause the flu. Side effects can be prevented by taking over-the-counter medicines such as acetaminophen. Never give your child aspirin without talking to your child's healthcare provider first. Possible side effects of the flu vaccine include:            

  • Soreness in the arm where the shot was given

  • Short-term symptoms such as mild headache or a low-grade fever for about 1 day after the shot

  • In rare cases, an allergic reaction in a child who has a severe allergy to eggs. Vaccines are available for those with an egg allergy.

In addition to the flu vaccine, you can do other things to help reduce your child’s risk of getting the flu. You can also:

  • Limit your child’s contact with infected people, if possible.

  • Have your child wash his or her hands often

And you can help prevent your child spreading the flu to others if you:

  • Have your child cover his or her nose and mouth when coughing or sneezing. Use a tissue or cough or sneeze in the crook of the arm.

  • Wash your hands before and after caring for your child.

  • Clean surfaces in the home that others may touch.

When should I call my child's healthcare provider?

Call the healthcare provider if your child has:

  • Symptoms that don’t get better, or get worse

  • New symptoms

Key points about the flu in children

  • Influenza (flu) is a very contagious viral infection of the respiratory system.

  • It causes a high fever, body aches, a cough, and other symptoms.

  • Most children are ill with the flu for less than a week. But some children have a more serious illness and may need to be treated in the hospital. The flu may also lead to lung infection (pneumonia) or death.

  • The flu may be treated with acetaminophen, cough medicine, and antiviral medicine. Your child will also need lots of rest and plenty of fluids.

  • The best way to prevent flu is to have the yearly flu vaccine. Because the viruses change, researchers create a new flu vaccine each year to help protect against strains of the virus that are currently active. The vaccine is advised for all children 6 months and older.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

  • Know the reason for the visit and what you want to happen.

  • Before your visit, write down questions you want answered.

  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.

  • Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.

  • Ask if your child’s condition can be treated in other ways.

  • Know why a test or procedure is recommended and what the results could mean.

  • Know what to expect if your child does not take the medicine or have the test or procedure.

  • If your child has a follow-up appointment, write down the date, time, and purpose for that visit.

  • Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.