About Flu

Influenza (commonly called “the flu”) is a contagious respiratory illness caused by influenza viruses. Infection with influenza viruses can result in severe illness and life-threatening complications. An estimated 10% to 20% of U.S. residents get the flu each year: an average of 114,000 people are hospitalized for flu-related complications and 36,000 Americans die each year from complications of flu.

Symptoms of Flu

Symptoms of flu include fever (usually high), headache, extreme tiredness, dry cough, sore throat, runny or stuffy nose, and muscle aches. Gastro-intestinal symptoms, such as nausea, vomiting, and diarrhea, are much more common among children than adults.

Spread of Flu

Influenza viruses are spread when a person who has the flu coughs, sneezes, or speaks and spreads virus into the air, and other people inhale the virus. When these viruses enter the nose, throat, or lungs of a person, they begin to multiply, causing symptoms of the flu. The viruses can also be spread when a person touches a surface with flu viruses on it (for example, a door handle) and then touches his or her nose or mouth.

A person who is sick with the flu can spread viruses - that means they are contagious. Adults may be contagious from 1 day before developing symptoms to up to 7 days after getting sick. Children can be contagious for longer than 7 days.

Preventing Flu

Vaccination: The single best way to prevent the flu is to get vaccinated each fall. In the absence of vaccine, however, there are other ways to protect against flu.

Antiviral Medications: Three antiviral drugs (amantadine, rimantadine, and oseltamivir) are approved and commercially available for use in preventing flu. All of these medications are prescription drugs, and a doctor should be consulted before the drugs are used for preventing the flu.

Other Habits for Good Health

The following steps may help prevent the spread of respiratory illnesses like flu:

• 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.

Diagnosing the Flu

Tests are available that can determine if you have the flu as long as you are tested within the first 2 or 3 days after your symptoms begin. In addition, a doctor's examination may be needed to determine whether a person has another infection that is a complication of the flu.

At Special Risk of Complications From Flu

Certain people are at increased risk for serious complications from the flu. This group includes people age 65 years and older and people of any age with chronic medical conditions. Pregnant women and children between 6 months and 23 months of age also are at increased risk from flu complications.

Complications From Flu

Some of the complications caused by flu include bacterial pneumonia, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes. Children may get sinus problems and ear infections. 

Treating the Flu

Antiviral Medications: Four antiviral drugs (amantadine, rimantadine, zanamavir and oseltamivir) have been approved for treatment of the flu. All of these must be prescribed by a doctor. Antiviral treatment lasts for 5 days and must be started within the first 2 days of illness.

What to Do If You Get Sick This Flu Season

If you develop the flu, it is advisable to get plenty of rest, drink a lot of liquids, and avoid using alcohol and tobacco. Also, you can take medications to relieve the symptoms of flu (but never give aspirin to children or teenagers who have flu-like symptoms - and particularly fever - without first speaking to your doctor.)

If, however, your flu symptoms are unusually severe (for example, if you are having trouble breathing), you should consult your health-care provider right away.

If you are at special risk from complications of flu, you should consult your health-care provider when your flu symptoms begin. This includes people 65 years or older, people with chronic medical conditions, pregnant women, or children . Your doctor may choose to use certain antiviral drugs to treat the flu.

For more information, visit www.cdc.gov/flu, or call the National Immunization Hotline at (800) 232-2522 (English), (800) 232-0233 (español), or (800) 243-7889 (TTY).