Influenza immunization for children

Influenza, commonly known as "the flu," is a contagious respiratory disease caused by the influenza virus. The virus attacks the respiratory tract -- nose, throat and lungs. In the United States, the flu season can peak anywhere from late December through March. Millions of people in the United States get the flu each year.

Two types of influenza vaccine are now available. The inactivated (killed) influenza vaccine, sometimes called the "flu shot," has been used for many years. As the name implies, the flu shot is given by injection. A live, intranasal influenza vaccine (FluMist, for example) was licensed in 2003. FluMist is an attenuated (weakened) live vaccine sprayed into the nostrils rather than injected into the muscle.

Inactivated vaccine, or flu shot (Fluogen, Flu-shield, Fluzone)


Recommendations
The inactivated influenza vaccine (flu shot) is recommended annually for people who are at risk of serious influenza or its complications and for people who can spread influenza to those at high risk. Because there were concerns about a shortage of flu shots for the 2005-2006 season, the Centers for Disease Control and Prevention (CDC) recommended that the following groups receive priority until late fall 2005:
evacuees from Hurricane Katrina age 6 months and older living in crowded conditions
children age 6 months to 23 months
children who live in a long-term care facility
children ages 2 and older who have chronic health conditions (heart disease or diabetes, for example) or a weak immune system (due to cancer or HIV, for example)
anyone who will be pregnant during the flu season
household contacts of children younger than age 6 months
An annual flu shot continues to be recommended for children who:

have any neuromuscular condition (such as a seizure disorder or spinal cord injury) that may affect their ability to breathe or manage respiratory secretions
are ages 6 months to 18 years on long-term aspirin therapy (A link exists between Reye's syndrome and aspirin use following a viral infection such as the flu.)
are in contact with other children or adults listed in the priority group above
live in dormitories or other crowded conditions
travel to the southern hemisphere between April and September or the tropics at any time
want to reduce the risk of getting the flu
Other healthy children older than age 5 years and adolescents who aren't pregnant are encouraged to be vaccinated with the live, intranasal vaccine, especially when supplies of inactivated vaccine are limited.


Dose
Children ages 8 and younger who've never been vaccinated need two doses, given at least one month apart. For all other children, a single shot is sufficient.

Effectiveness
When the circulating flu viruses are similar to the virus strains in the vaccine, the flu vaccine may be as much as 90 percent effective in preventing the flu. The effectiveness varies with the age and health of the child, with protection being the greatest in older healthy children. It takes one to two weeks for the vaccine to be effective. (The best time to receive the vaccine in the United States is in October or November, although the vaccine is usually available from September to December.) If given too early, immunity may decline before the flu season ends. If given too late, there's a risk of getting the flu before protection begins.
For those who get the flu even after receiving the vaccine, the severity of symptoms and frequency of complications may be reduced.


Side effects
Side effects are usually mild, typically including tenderness, redness or a lump at the injection site, lasting up to two days, beginning six to 48 hours after the vaccination. Less common reactions may include fever, chills, malaise or muscle aches. An allergic reaction is possible, but rare. (In 1976, the Guillain-Barre syndrome was associated with the flu vaccine. Since then, the condition hasn't been clearly associated with the vaccine. If there's a risk today, it's extremely rare.)

Who should wait to get this vaccine?
Your child's doctor may postpone this vaccine if your child has a moderate to severe acute illness.

Who shouldn't get this vaccine?
Your child shouldn't get this vaccine if he or she has had a severe allergic reaction to a prior dose of the vaccine or any vaccine component (such as eggs). If your child has a history of Guillain-Barre syndrome, the immunization may not be recommended. It's also not given to children younger than age 6 months.
Live, intranasal vaccine, or nasal spray vaccine (FluMist)


Recommendations
The live, intranasal influenza vaccine may be used by healthy children ages 5 years and older, including household contacts of people at high risk for influenza complications.

Dose
From ages 5 years to 8 years, two doses of the nasal spray vaccine are recommended six to 10 weeks apart. The first dose should be given in October or earlier. Older children need only a single dose.

Effectiveness
In one study, the nasal spray vaccine reduced the risk of flu for children by more than 90 percent.

Side effects
Side effects are usually mild, and may include runny nose, nasal congestion, fever, headache, muscle aches, abdominal pain or occasional vomiting. An allergic reaction is possible, but rare.

Who should wait to get the vaccine?
Your child's doctor may postpone the vaccine if your child has a moderate to severe acute illness or nasal congestion. (Nasal congestion may limit absorption of the vaccine.)

Who shouldn't get the vaccine?
CONTRAINDICATED for pregnant adolescents, children younger than age 5 and those who are receiving aspirin, have a history of a chronic medical condition or weakened immune system, have a history of Guillain-Barre syndrome, or are allergic to eggs or any vaccine component.