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Influenza Vaccine, Inactivated

Why get vaccinated?   Return to top

Influenza (''flu'') is a contagious disease. It is caused by the influenza virus, which spreads from infected persons to the nose or throat of others. Other illnesses can have the same symptoms and are often mistaken for influenza. But only an illness caused by the influenza virus is really influenza.

Anyone can get influenza, but rates of infection are highest among children. For most people, it lasts only a few days. It can cause: fever, sore throat, chills, fatigue, cough, headache, and muscle aches.

Some people get much sicker. Influenza can lead to pneumonia and can be dangerous for people with heart or breathing conditions. It can cause high fever and seizures in children. On average, 226,000 people are hospitalized every year because of influenza and 36,000 die - mostly elderly.

Influenza vaccine can prevent influenza.

Inactivated Influenza vaccine   Return to top

There are two types of influenza vaccine:

• An inactivated (killed) vaccine, or ''flu shot,'' is given by injection into the muscle.
• Live, attenuated (weakened) influenza vaccine, called LAIV, is sprayed into the nostrils. This vaccine is described in a separate monograph.

For most people influenza vaccine prevents serious influenzarelated illness. But it will not prevent ''influenza-like'' illnesses caused by other viruses.

Influenza viruses are always changing. Because of this, influenza vaccines are updated every year, and an annual vaccination is recommended. Protection lasts up to a year.

It takes about 2 weeks for protection to develop after the vaccination.

Some inactivated influenza vaccine contains thimerosal, a preservative that contains mercury. Some people believe thimerosal may be related to developmental problems in children. In 2004 the Institute of Medicine published a report concluding that, based on scientific studies, there is no evidence of such a relationship. If you are concerned about thimerosal, ask your doctor about thimerosal-free influenza vaccine.

Who should get inactivated influenza vaccine?   Return to top

People 6 months of age and older can receive inactivated influenza vaccine. It is recommended for anyone who is at risk of complications from influenza or more likely to require medical care:

• All children from 6 months up to 5 years of age.
• Anyone 50 years of age or older.
• Anyone 6 months to 18 years of age on long-term aspirin treatment (they could develop Reye Syndrome if they got influenza).
• Women who will be pregnant during influenza season.
• Anyone with long-term health problems with heart disease; kidney disease; lung disease; metabolic disease, such as diabetes; asthma; anemia, and other blood disorders.
• Anyone with a weakened immune system due to HIV/AIDS or other diseases affecting the immune system; long-term treatment with drugs such as steroids; cancer treatment with x-rays or drugs.
• Anyone with certain muscle or nerve disorders (such as seizure disorders or severe cerebral palsy) that can lead to breathing or swallowing problems.
• Residents of nursing homes and other chronic-care facilities.

Influenza vaccine is also recommended for anyone who lives with or cares for people at high risk for influenzarelated complications:

• Health care providers.
• Household contacts and caregivers of children from birth up to 5 years of age.
• Household contacts and caregivers of people 50 years and older, and those with medical conditions that put them at higher risk for severe complications from influenza.

A yearly influenza vaccination should be considered for:

• People who provide essential community services.
• People living in dormitories or under other crowded conditions, to prevent outbreaks.
• People at high risk of influenza complications who travel to the Southern hemisphere between April and September, or to the tropics or in organized tourist groups at any time.

Influenza vaccine is also recommended for anyone who wants to reduce the likelihood of becoming ill with influenza or spreading influenza to others.

When should I get influenza vaccine?   Return to top

Plan to get influenza vaccine in October or November if you can. But getting vaccinated in December, or even later, will still be beneficial in most years. You can get the vaccine as soon as it is available, and for as long as illness is occurring. Influenza illness can occur any time from November through May. Most cases usually occur in January or February.

Most people need one dose of influenza vaccine each year. Children younger than 9 years of age getting influenza vaccine for the first time should get 2 doses. For inactivated vaccine, these doses should be given at least 4 weeks apart.

Influenza vaccine may be given at the same time as other vaccines, including pneumococcal vaccine.

Some people should talk with a doctor before getting influenza vaccine   Return to top

Some people should not get inactivated influenza vaccine or should wait before getting it.

• Tell your doctor if you have any severe (life-threatening) allergies. Allergic reactions to influenza vaccine are rare. Influenza vaccine virus is grown in eggs. People with a severe egg allergy should not get the vaccine. A severe allergy to any vaccine component is also a reason to not get the vaccine. If you have had a severe reaction after a previous dose of influenza vaccine, tell your doctor.
• Tell your doctor if you ever had Guillain-Barré Syndrome (a severe paralytic illness, also called GBS). You may be able to get the vaccine, but your doctor should help you make the decision.
• People who are moderately or severely ill should usually wait until they recover before getting flu vaccine. If you are ill, talk to your doctor or nurse about whether to reschedule the vaccination. People with a mild illness can usually get the vaccine.

What are the risks from inactivated influenza vaccine?   Return to top

A vaccine, like any medicine, could possibly cause serious problems, such as severe allergic reactions. The risk of a vaccine causing serious harm, or death, is extremely small.

Serious problems from influenza vaccine are very rare.The viruses in inactivated influenza vaccine have been killed, so you cannot get influenza from the vaccine.

Mild Problems:

• soreness, redness, or swelling where the shot was given
• fever
• aches
• If these problems occur, they usually begin soon after the shot and last 1-2 days.

Severe Problems:

• Life-threatening allergic reactions from vaccines are very rare. If they do occur, it is within a few minutes to a few hours after the shot.
• In 1976, a certain type of influenza (swine flu) vaccine was associated with Guillain-Barré Syndrome (GBS). Since then, flu vaccines have not been clearly linked to GBS. However, if there is a risk of GBS from current flu vaccines, it would be no more than 1 or 2 cases per million people vaccinated. This is much lower than the risk of severe influenza, which can be prevented by vaccination.

What if there is a severe reaction?   Return to top

What should I look for?

• Any unusual condition, such as a high fever or behavior changes. Signs of a serious allergic reaction can include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heart beat or dizziness.

What should I do?

• Call a doctor, or get the person to a doctor right away.
• Tell your doctor what happened, the date and time it happened, and when the vaccination was given.
• Ask your health care provider to file a Vaccine Adverse Event Reporting System (VAERS) form if you have any reaction to the vaccine. Or call VAERS yourself at 1-800-822-7967, or visit their website at http://vaers.hhs.gov.

The National Vaccine Injury Compensation Program   Return to top

In the rare event that you or your child has a serious reaction to a vaccine, a federal program has been created to help pay for the care of those who have been harmed.

For details about the National Vaccine Injury Compensation Program, call 1-800-338-2382 or visit the program's website at http://www.hrsa.gov/vaccinecompensation.

How can I learn more?   Return to top

• Ask your doctor or other health care provider. They can give you the vaccine package insert or suggest other sources of information.
• Call your local or state health department's immunization program.
• Contact the Centers for Disease Control and Prevention (CDC): call 1-800-232-4636 (1-800-CDC-INFO) or visit the National Immunization Program's website at http://www.cdc.gov/vaccines.

Inactivated Influenza Vaccine Information Statement. U.S. Department of Health and Human Services/Centers for Disease Control and Prevention National Immunization Program. 7/16/2007.

Brand names   Return to top

Last Revised - 08/01/2007
Last Reviewed - 08/01/2007

American Society of Health-System Pharmacists, Inc. Disclaimer

The MedMaster™ Patient Drug Information database provides information copyrighted by the American Society of Health-System Pharmacists, Inc., Bethesda, Maryland Copyright© 2008. All Rights Reserved.

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