Pediatric Influenza

Updated for the 2025-2026 flu season

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.

Because of other illnesses such as COVID-19 and RSV, the CDC says getting a flu vaccine is more important than ever to protect yourself and the people around you from flu. Flu vaccines and other vaccines can be given at the same time. Talk with your doctor about vaccines.

The flu is caused by flu viruses. There are three types:

• Influenza types A and B. These two 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 countertops. 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 their 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 often ends about day five to seven of the illness. Because the flu can be spread before symptoms start, it’s easy to pick up a flu virus. This is especially true with children, who often touch many surfaces and then touch their mouth, nose or eyes.

A child is at greater risk for the flu if they:

• Are around people infected with the flu.
• Haven't had the flu vaccine.
• Don't wash their hands after touching infected surfaces.

Young children and children with certain health problems are at higher risk for a hospital stay or severe or complicated influenza infection.

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 three to four weeks.

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

Cold Symptoms:

• Low or no fever
• Sometimes a headache
• Stuffy, runny nose
• Sneezing
• Mild, hacking cough
• Mild body aches
• Mild tiredness
• Sore throat

Flu Symptoms:

• High fever
• Headache in most cases
• Clear nose, or stuffy nose in some cases
• Sneezing in some cases
• Cough, often turning severe
• Severe body aches
• Extreme tiredness (fatigue) that can last weeks
• 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. Many flu symptoms may be caused by other health problems. Make sure your child sees their doctor for a diagnosis.

The doctor will ask about your child’s symptoms and health history. They will give your child a physical exam. The symptoms are often enough to diagnose the flu. Other tests may be done such as a nose or throat swab. This depends on your child’s symptoms and overall health.

Treatment will depend on your child’s symptoms, age and general health. It will also depend on how bad the condition is. The goal of treatment is to help prevent or ease symptoms.

Treatment may include medicines such as:

• Acetaminophen. This help can help reduce body aches and fever. Do not give aspirin to children or teens unless your child’s doctor says it is safe. Aspirin can put your child at risk for Reye syndrome, a rare but serious condition.
• Antiviral medicine. This may help to ease symptoms and shorten the length of illness. The medicine can reduce the chance of developing an ear infection from the flu. It may also help decrease other complications, including the need for hospitalization. The medicine is most useful if started within 2 days after symptoms start. But it may be started later if the child is having complications or is at high risk for them.

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 doctors 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

The best way to prevent the flu is to make sure your child gets the yearly flu vaccine. Each year, a new flu vaccine is available before the flu season starts. Flu shots and nasal spray are available. Talk with your doctor 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 doctor 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, they 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. Then the second dose can be given by the end of October. This will give your child the best protection for the flu season. After your child's first flu season, they'll need only one dose.

The vaccine is advised for all children 6 months and older. But for some children, it’s more important 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 use of steroids or other immune-suppressing medicines
• 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 long-term (chronic) health condition.
• A child or teen taking aspirin as long-term therapy.
• A child with parents or caregivers at high risk for complications from the flu.

Some side effects of the vaccine can seem like mild flu symptoms. But the vaccine doesn't cause the flu. Side effects can be treated with over-the-counter medicines such as acetaminophen. Never give your child aspirin without first talking with your child's doctor. 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 one day after the shot.

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 their hands often.
• Have your child wear a medical mask when in contact with many others or in large groups of people.

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

• Have your child cover their nose and mouth when coughing or sneezing. Teach them to use a tissue or cough or sneeze in the crook of their arm.
• Wash your hands before and after caring for your child.
• Clean surfaces in the home that others may touch.

Contact the doctor if:

• Symptoms that don’t get better or get worse
• New symptoms