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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 are responsible for epidemics of respiratory illness that occur almost every winter and 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 recognizes the "newer" virus when the next flu season comes around.

  4. The person becomes infected again.

The older antibodies can, however, give some protection against getting the flu again. Currently, three different influenza viruses circulate worldwide: two type A viruses and one type B virus. 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 infected person who sneezes or coughs. The virus can also live for a short time on objects 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 consult your child's doctor 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, although sometimes it 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, could, in fact, 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 influenza be prevented?

A new influenza vaccine is introduced each September. All children at least 6 months old should get the flu vaccine this season as soon as it is available in their community. In addition, antiviral medications can be used to prevent the flu in children. All of these medications are available by prescription. Talk with your child's doctor before giving any medication to prevent the flu.

A nasal spray flu vaccine is currently approved to prevent flu caused by influenza A and B viruses in healthy children and adolescents ages 2 to 17 (and in healthy adults ages 18 to 49). As with other live virus vaccines, the nasal spray vaccine should not be given for any reason to pregnant women and people with immune suppression, including those with immune deficiency diseases, such as AIDS or cancer, and people who are being treated with medications that cause immunosuppression. It also should not be given to these groups of people:

  • Children younger than 2 years old

  • Any person with asthma or children younger than 5 who have recurrent wheezing 

  • Adults ages 50 and older

  • Children and adolescents who are taking aspirin as long-term treatment

  • Children and adults who have a chronic disorder of the lung, heart, kidney, liver, nerves, blood, or metabolism

Following these precautions may be helpful:

  • When possible, avoid or limit contact with infected people.

  • Frequent handwashing may reduce, but not eliminate, the risk for infection.

  • A person who is coughing or sneezing should cover his or her nose and mouth with a tissue or inside elbow to limit spread of the virus.

Vaccine effectiveness varies from year to year, depending on how close the influenza virus strains included in the vaccine match strain or strains that actually circulate during the influenza season. Vaccine strains must be chosen 9 to 10 months before the influenza season. Sometimes, changes occur in the circulating strains of viruses between the time vaccine strains are chosen and the next influenza season. These changes may reduce the ability of the vaccine-induced antibodies to stop the newly mutated virus. This decreases the chance that the vaccine will work.

Vaccine effectiveness also varies from one person to another, depending on factors like age and overall health.

What are the side effects of the vaccine?

The most serious side effect that can occur after influenza vaccination is an allergic reaction in people who have a severe allergy to eggs. For this reason, children who have an allergy to eggs should not get the influenza vaccine. According to the National Center for Infectious Diseases, part of the CDC, influenza vaccine causes no side effects in most children who are not allergic to eggs.

Some people who receive the vaccine have soreness at the vaccine site, and some people have mild side effects, such as a headache or a low-grade fever for about a day after vaccination. Because these mild side effects mimic some influenza symptoms, some people believe influenza vaccine causes them to get influenza. But the CDC says that "influenza vaccine produced in the United States has never been capable of causing influenza because the only type of influenza vaccine that has been licensed in the United States to the present time is made from killed influenza viruses, which cannot cause infection."

What are current vaccine recommendations?

While the 2013-2014 flu vaccine will protect you from the same viruses as last year, it's still important to get an annual flu shot because immunity decreases over time. The vaccine is recommended for all people 6 months and older, including pregnant women. People who are allergic to eggs or other components of the vaccine may be told not to get the vaccine. It is especially important that these groups receive the vaccine: 

  • Pregnant women and women who anticipate they may be pregnant during flu season  

  • People 50 and older. Vaccine effectiveness may be lower for older adults, but it can significantly reduce their chances of serious illness or death from influenza.

  • Children 6 months to 19 years old

  • Residents of nursing homes and any other chronic care facilities that house people of any age who have chronic medical conditions

  • Adults and children who have chronic disorders of the pulmonary or cardiovascular systems, including children with asthma, cystic fibrosis, and chronic lung disease of infancy, such as bronchopulmonary dysplasia

  • Adults and children who have the following medical conditions:

    • Chronic metabolic diseases, such as diabetes

    • Renal dysfunction

    • Immunosuppression

    • Hemoglobinopathies

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

  • Health care providers

  • Employees of nursing homes and chronic care facilities who have contact with patients or residents

  • Providers of home care to people at high risk

  • Household members, including children, of people in high-risk groups

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

  • Extent of the condition

  • 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 to relieve aches and fever. Aspirin should not be given to children with a fever without first consulting your child's doctor. The drug of choice for children is acetaminophen.

  • Medications used for congestion and nasal discharge

  • Bed rest

  • Increased fluid intake

  • Medication for your child's cough may be prescribed by your child's doctor after a thorough evaluation.

  • Antiviral medications may help to shorten the duration of the illness and to decrease the severity of the flu, but do not cure the flu. They must be started within three days after symptoms begin to have an effect on the virus. The length of therapy will be determined by your child's doctor. Antiviral medications may also be given as prophylaxis or prevention following exposure to someone with influenza.