Influenza - Prevention

Prevention

You can help prevent influenza by getting immunized with an influenza vaccine each year, ideally in October or November. The inactivated influenza vaccine(What is a PDF document?) commonly known as the "flu shot," is given by injection. This form of the vaccine effectively prevents most cases of the flu, although success rates vary according to age, health status, and how closely the virus strains contained in the vaccine match those that are circulating through the population.

Even if a flu shot does not prevent the flu, the vaccine can reduce the severity of flu symptoms and decrease the risk of complications. Studies have found that the flu shot results in fewer days missed from work and fewer visits to a doctor for respiratory infections, and it reduces the number of people who develop complications from the flu, such as pneumonia.⁵

In spite of these results, many people choose not to get a flu shot. Some do not get the shot because of myths they believe about the flu or the vaccine. The flu shot may cause side effects in some people, but they are usually minor and do not last long.

For help deciding if the flu shot is right for you, see:

Should I get a flu shot?

An alternative to the flu shot is now available. In 2003, the U.S. Food and Drug Administration (FDA) approved a nasal spray flu vaccine(What is a PDF document?). Healthy people ages 2 through 49 years can usually get the nasal spray form of the vaccine, called FluMist. The nasal spray vaccine contains components of live viruses, so it should not be given to people with certain long-term (chronic) health conditions, such as heart or lung problems. Close contacts of these people in high-risk categories can be given either type of vaccine, with one rare exception. Immunization with the inactivated virus (flu shot) is preferred over the nasal spray vaccine for close contacts of people with severely impaired immune systems during times when a protected environment is needed. This avoids the risk of transmitting an active flu virus from the nasal spray vaccine. If the nasal spray vaccine is used, contact with anyone in this high-risk group should be avoided for 7 days. For close contacts of people in all other high-risk categories, vaccination with either the flu shot or the nasal spray is considered safe.⁵

You should not use FluMist if you:

• Have heart disease.
• Have lung disease, including asthma.
• Have diabetes or kidney disease.
• Have a disease or take a medicine that causes problems with your immune system.
• Have had Guillain-Barré syndrome.
• Are pregnant.
• Have ever had an allergic reaction to FluMist or to eggs.
• Are younger than age 20 and you take aspirin or products with aspirin in them.

Because the FluMist nasal vaccine is more expensive than a flu shot, it may not be covered by your health insurance plan. Check with your insurance company.

Other ways to reduce your risk of getting the flu or developing complications

Increase your chance of staying healthy by:

• Washing your hands often, especially during winter months when the flu is most common.
• Keeping your hands away from your nose, eyes, and mouth. Viruses are most likely to enter your body through these areas.
• Eating a healthy and balanced diet.
• Getting regular exercise.
• Not smoking. Smoking irritates the lining of your nose, sinuses, and lungs, which may make you susceptible to complications of the flu.

Using antiviral medications to prevent the flu

The antiviral medications amantadine and rimantadine have been used to prevent flu caused by influenza A. But for the past few years the U.S. Centers for Disease Control and Prevention (CDC) has advised doctors not to use these medicines to treat or prevent the flu.⁴ These medicines have not worked against most types of the flu virus. Amantadine and rimantadine do not protect against influenza B. It is important to talk with your doctor about the medicine that is best for you.

Two other antiviral medications (zanamivir and oseltamivir) can prevent the flu caused by influenza A and B viruses. These medications may also reduce the length of the illness if they are given no more than 48 hours after the first symptoms. During a flu outbreak, these medications may be given at the same time as the flu shot and for 2 weeks after while your body produces antibodies to protect you from the virus. These medications are taken by mouth (pill) or inhaled into the lungs (inhaler).

Some people cannot have a flu shot because they are allergic to eggs, from which the vaccine is made.

For more information, see:

Should I take antiviral medicine for the flu?