The Influenza Vaccine: What You Need to Know

Why Get Vaccinated?

Influenza is a serious disease.

It is caused by a virus that spreads from infected persons to the nose or throat of others. The "influenza season" in the U.S. is from November through April each year.

Influenza can cause:

• Fever
• Cough
• Chills
• Sore throat
• Headache
• Muscle aches

People of any age can get influenza. Most people are ill with influenza for only a few days, but some get much sicker and may need to be hospitalized. Influenza causes thousands of deaths each year, mostly among the elderly.

Influenza vaccine can prevent influenza.

Influenza Vaccine

Influenza viruses change often. Therefore, influenza vaccine is updated each year to make sure it is as effective as possible.

Protection develops about two weeks after getting the shot and may last up to a year.

Who Should Get Influenza Vaccine?

People at risk for getting a serious case of influenza or influenza complications, and people in close contact with them (including all household member) should get the vaccine. An annual flu shot is recommended for these groups:

• Everyone 50 years of age or older
• residents of long term care facilities housing persons with chronic conditions.
• Anyone who has a serious long-term health problem with:
  • Heart disease
  • Lung disease
  • Asthma
  • Kidney disease
  • Metabolic disease, such as Diabetes
  • Anemia, and other blood disorders
• Anyone whose immune system is weakened because of:
  • HIV/AIDS or other diseases that effect the immune system
  • Long-term treatment with drugs such as steroids
  • Cancer treatment with x-rays or drugs
• Anyone six months to 18 years of age on long-term asprin treatment (who could develop Reye Syndrome if they catch influenza.)
• Women who will be past the third month of pregnancy during the influenza season
• Physicians, nurses, family members, or anyone else coming in close contact with people at risk of serious influenza.

Others who should consider getting influenza vaccine:

• People who provide essential community services.
• Persons traveling to the Southern hemisphere between April and September, or to the tropics at any time.
• Persons living in dormitories or in other crowded conditions, to prevent outbreaks.
• Anyone who wants to reduce their chance of catching influenza.

When Should I Get Influenza Vaccine?

Because influenza activity can start as early as December, the best time to get influenza vaccine is during October and November. But getting the vaccine after November can still provide protection. A new shot is needed each year.

• People nine years of age and older need one shot.
• Children younger than 9 years old need two shots, given one month apart, the first time they get vaccinated against influenza.

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

Can I Get Influenza Even if I Get the Vaccine This Year?

Yes. Influenza viruses change often, and they might not always be covered by the vaccine. But vaccinated people who do get influenza often have milder cases than those who did not get the shot.

Also, many people call any illness with fever and cold symptoms "the flu." They may expect influenza vaccine is effective only against illness caused by influenza viruses, and not against other illnesses.

Some People Should Talk With a Doctor Before Getting Influenza Vaccine.

Talk with a doctor before getting an influenza vaccination if you:

• Have had a serious allergic reaction to eggs or to a previous dose of influenza vaccine or
• Have a history of Guillain-Barré Syndrome (GBS.)

If you ever have a fever or are severely ill at the time the shot is scheduled you should usually wait until you recover before getting influenza vaccine. Talk to your doctor or nurse about whether to reschedule the vaccination.

What Are The Risks From Influenza Vaccine?

A vaccine, like any medicine, is capable of causing serious problems, such as severe allergy reactions. The risks of a vaccine causing serious harm, or death, is extremely small. Almost all people who get influenza vaccine have no serious problems from it. The viruses in the vaccine are 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 are very rare. If they do occur, it is within a few minutes to a few hours after the shot.
• In 1976, swine flu vaccine was associated with a severe paralytic illness called Guillain-Barré Syndrome (GBS.) Influenza vaccines since then have not been clearly linked to GBS. However, if there is a risk of GBS from current influenza vaccines, it is estimated at 1 or 2 cases per million persons vaccinated... much less than the risk of severe influenza, which can be prevented by vaccination.

What if There is a Moderate or Severe Reaction?

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 doctor, nurse, or health department to a file a Vaccine Adverse Event Reporting System (VAERS) form, or call VAERS yourself at 1-800-822-7967.

How Can I Learn More?

• Ask your doctor or nurse. They can give you the vaccine package insert or suggest other sources of information.
• Call your local or state health department.
• Contact the Centers for Disease Control and Prevention (CDC):
  • Call 1-800-232-2522 (English)
  • Call 1-800-232-0233 (Español)
• Visit the CDC National Immunization Program's website.