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Are You Ready for Flu Season?

Good Health Habits for Preventing the Flu

The single best way to prevent the flu is to get vaccinated each year, but good health habits and antiviral medications are other measures that can help protect against the flu.

Good Health Habits

• Avoid close contact. Avoid close contact with people who are sick. When you are sick, keep your distance from others to protect them from getting sick too.
• Stay home when you are sick. If possible, stay home from work, school, and errands when you are sick. You will help prevent others from catching your illness.
• Cover your mouth and nose. Cover your mouth and nose with a tissue when coughing or sneezing. It may prevent those around you from getting sick.
• Clean your hands. Washing your hands often will help protect you from germs.
• Avoid touching your eyes, nose or mouth. Germs are often spread when a person touches something that is contaminated with germs and then touches his or her eyes, nose, or mouth.
• Practice other good health habits. Get plenty of sleep, be physically active, manage your stress, drink plenty of fluids, and eat nutritious food.

Key Facts about Influenza (Flu) Vaccine

The single best way to protect against the flu is to get vaccinated each year.

There are two types of vaccines:

• The "flu shot" - an inactivated vaccine (containing killed virus) that is given with a needle, usually in the arm. The flu shot is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions.
• The nasal-spray flu vaccine-a vaccine made with live, weakened flu viruses that do not cause the flu (sometimes called LAIV for "Live Attenuated Influenza Vaccine"). LAIV is approved for use in healthy people 5 years to 49 years of age who are not pregnant.

Each vaccine contains three influenza viruses-one A (H3N2) virus, one A (H1N1) virus, and one B virus. The viruses in the vaccine change each year based on international surveillance and scientists' estimations about which types and strains of viruses will circulate in a given year.

About 2 weeks after vaccination, antibodies that provide protection against influenza virus infection develop in the body.

When to Get Vaccinated

October or November is the best time to get vaccinated, but you can still get vaccinated in December and later. Flu season can begin as early as October and last as late as May.

Who Should Get Vaccinated

In general, anyone who wants to reduce their chances of getting the flu can get vaccinated. However, it is recommended by ACIP that certain people should get vaccinated each year. They are either people who are at high risk of having serious flu complications or people who live with or care for those at high risk for serious complications. During flu seasons when vaccine supplies are limited or delayed, ACIP makes recommendations regarding priority groups for vaccination (see www.cdc.gov/flu/about/qa/flushot.htm. )

People who should get vaccinated each year are:

1. People at high risk for complications from the flu, including:

• Children aged 6 months until their 5th birthday,
• Pregnant women,
• People 50 years of age and older, and
• People of any age with certain chronic medical conditions;
• People who live in nursing homes and other long term care facilities.

2. People who live with or care for those at high risk for complications from flu, including:

• Household contacts of persons at high risk for complications from the flu (see above)
• Household contacts and out of home caregivers of children less than 6 months of age (these children are too young to be vaccinated)
• Healthcare workers

Use of the Nasal Spray Flu Vaccine

It should be noted that vaccination with the nasal-spray flu vaccine is always an option for healthy persons aged 5-49 years who are not pregnant.

Who Should Not Be Vaccinated

There are some people who should not be vaccinated without first consulting a physician. These include

• People who have a severe allergy to chicken eggs.
• People who have had a severe reaction to an influenza vaccination in the past.
• People who developed Guillain-Barr? syndrome (GBS) within 6 weeks of getting an influenza vaccine previously (see www.cdc.gov/flu/about/qa/gbs.htm .
• Influenza vaccine is not approved for use in children less than 6 months of age.
• People who have a moderate or severe illness with a fever should wait to get vaccinated until their symptoms lessen.

Vaccine Effectiveness

The ability of flu vaccine to protect a person depends on the age and health status of the person getting the vaccine, and the similarity or "match" between the virus strains in the vaccine and those in circulation. Testing has shown that both the flu shot and the nasal-spray vaccine are effective at preventing the flu.

Vaccine Side Effects (What to Expect)

Different side effects can be associated with the flu shot and LAIV.

The flu shot: The viruses in the flu shot are killed (inactivated), so you cannot get the flu from a flu shot. Some minor side effects that could occur are

• Soreness, redness, or swelling where the shot was given
• Fever (low grade)
• Aches

If these problems occur, they begin soon after the shot and usually last 1 to 2 days. Almost all people who receive influenza vaccine have no serious problems from it. However, on rare occasions, flu vaccination can cause serious problems, such as severe allergic reactions. As of July 1, 2005, people who think that they have been injured by the flu shot can file a claim for compensation from the National Vaccine Injury Compensation Program (VICP). For more information, go to www.hrsa.gov/osp/vicp

LAIV: The viruses in the nasal-spray vaccine are weakened and do not cause severe symptoms often associated with influenza illness. (In clinical studies, transmission of vaccine viruses to close contacts has occurred only rarely.)

In children, side effects from LAIV can include

• runny nose
• headache
• vomiting
• muscle aches
• fever

In adults, side effects from LAIV can include

• runny nose
• headache
• sore throat
• cough

Antiviral Drugs and Influenza

Please note the publication "Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP) (MMWR 2006 Jul 28;55(RR10):1-42)" In which ACIP recommends that neither amantadine nor rimantadine be used for the treatment or prevention of influenza A in the United States for the 2006-07 influenza season.

Four antiviral medications (amantadine, rimantadine, zanamavir and oseltamivir*) have been approved by the U.S. Food and Drug Administration (FDA) for treatment of influenza. However, you will need to begin taking the medication within 2 days after becoming sick. When used in this manner, these medications can reduce influenza symptoms and may shorten the time you are sick by 1 or 2 days. They also may make you less contagious. All of these medications must be prescribed by a doctor and taken for 3-5 consecutive days (5 days for oseltamivir and zanamivir). The 4 antiviral medications are effective only against influenza viruses. They will not help symptoms associated with the common cold or many other influenza-like illnesses caused by viruses that circulate in the winter.

All four antiviral medications (amantadine, rimantadine, and oseltamivir) also are approved by the FDA and are commercially available for use in the United States to prevent influenza. All of these medications are prescription drugs, and a doctor should be consulted before the drugs are used. When used for prevention, they are about 70% to 90% effective in preventing illness in healthy adults.

All of the antiviral medications may be effective for influenza A viruses. However, only oseltamivir and zanamivir are effective for influenza B viruses. Also, recent evidence indicates that a high proportion of currently circulating influenza A viruses in the United States have developed resistance to amantadine and rimantadine. Please see the January 14, 2006 Health Alert Notice for more information.

All of the antiviral medications are different in terms of who can take them, how they are given, any dosing changes based on age or medical conditions, and side effects. Your doctor can help decide whether you should take an antiviral drug and which one you should use.

Use of Antiviral Medications

Antiviral medications are most often used to help control influenza outbreaks in institutions, for example in nursing homes or in hospital wards, where people at high risk for complications from influenza are in close contact with each other. Antiviral medications also have been used on cruise ships or similar settings to help control influenza outbreaks.

In the event of an outbreak, public health practice is to combine the use of influenza vaccine and antiviral medications. For example, nursing home residents and staff are given vaccine during an outbreak and also are given antiviral medications to prevent influenza until the vaccine takes effect (about 2 weeks). This practice continues as long as influenza is occurring in that setting.

Doctors also can prescribe influenza antiviral medications to people not living in institutional settings, but treatment must begin within 2 days of the onset of symptoms for the drugs to be effective. Although all antiviral medications lessen symptoms and shorten the duration of illness, only one (oseltamivir) has been shown in a study to reduce lower respiratory tract complications requiring antibiotics. They do not cure influenza outright.

When considering the use of antiviral medications it is important to remember that most healthy people recover from influenza without complications.

Who Should Get Antiviral Medications

People who are at high risk of serious complications from influenza may benefit most from antiviral medications. This includes: people 65 years of age and older, children 12-23 months of age, people with chronic medical conditions (for example, heart or lung disease, diabetes), and pregnant women. (Note that none of the antiviral medications is approved for use in children less than 1 year of age.) Although CDC has provided guidelines for health-care professionals on the use of antiviral drugs, your doctor will decide whether you should receive antiviral medications this season. The guidelines for use of influenza antiviral medications are not intended as recommendations for use of these medications in other situations, such as outbreaks of new strains of avian influenza.

For Treatment: If you become sick with influenza-like symptoms this season, your doctor first may give you a test to find out whether you have influenza. (Symptoms include fever (usually high), headache, tiredness, a sore throat and dry cough, nasal congestion, and body aches.) Your doctor also will consider a number of factors before making a treatment decision, such as your risk for complications from influenza.

For Prevention: In the event of an influenza outbreak in a home, institution, or community, your doctor may choose to prescribe antiviral medications to you as a preventive measure, especially if you are at high risk for complications from influenza. Also, if you are in close contact with someone who is considered at high risk for complications, you may be given antiviral medications to reduce the chances of passing influenza to the high-risk person.

* Note: On November 13, 2006, FDA approved a labeling supplement for Roche Laboratories' Tamiflu (Oseltamivir Phosphate) to include a precaution about neuropsychiatric events. The revision is based on postmarketing reports (mostly from Japan) of self-injury and delirium with the use of Tamiflu in patients with influenza. The reports were primarily among pediatric patients. The relative contribution of the drug to these events is not known. However, people with the flu, particularly children, may be at an increased risk of self-injury and confusion shortly after taking Tamiflu and should be closely monitored for signs of unusual behavior. A healthcare professional should be contacted immediately if the patient taking Tamiflu shows any signs of unusual behavior. For more information, please visit the for FDA.

For more information, visit www.cdc.gov/flu, or call CDC at 800-CDC-INFO (English and Spanish) or 888-232-6358 (TTY).

Source: U.S. Department of Health and Human Services - Centers for Disease Control and Prevention

Adapted by Editorial Staff on December 2006
Last update, July 2008