INFLUENZA

Influenza, also known as "flu," is a common respiratory infection that can be severe and even life-threatening. Each year more than 36,000 persons, especially older individuals and those with chronic medical conditions, die from influenza in the United States. The February 23, 2005, issue of JAMA includes an article that evaluates the accuracy of diagnosing influenza. This Patient Page is adapted from one previously published in the November 3, 2004, issue of JAMA.

Symptoms and Signs of Influenza

Fever — often a high temperature of more than 102° Fahrenheit (38.9° Celsius)
Headache
Muscle aches and pains
Chills
Cough
Pleuritic chest pain (pain when you take a breath)
Gastrointestinal symptoms, such as nausea, vomiting and diarrhea, are rare in adults with influenza. What is sometimes called "stomach flu" is actually not caused by the flu virus. The medical term for that common condition is gastroenteritis.


Flu vs. Colds
Colds are also viral infections but are usually self-limited and not life threatening. Colds usually cause a stuffy or runny nose, sore throat, mild cough and sometimes mild fever.

Treating Influenza
Because influenza is a viral infection, it cannot be treated with antibacterial antibiotics. Several antiviral prescription medications are available that may help treat influenza. These medications work best if they are taken early in the course of the flu. They may help decrease the length of symptoms of influenza. These drugs cause some adverse effects, and persons with some chronic medical problems should not take them, nor should pregnant women. They are not recommended for children younger than 1 year. Medications for pain and fever may also be helpful in relieving flu symptoms.

Preventing Influenza
Receiving flu vaccine each year is the best way to prevent influenza. Yearly vaccinations against influenza are recommended particularly for everyone aged 65 years and older, pregnant women, individuals with chronic medical problems (such as asthma, diabetes or heart disease), health care workers, individuals who care for children or elderly persons, all children aged 6 to 23 month and older children who have chronic medical conditions or who are receiving chronic aspirin therapy. Children 8 years and younger receiving the flu vaccine for the first time should receive two doses given about 30 days apart.

The flu shot is made from inactivated influenza virus and cannot give you the flu. Because influenza virus strains differ from year to year, the influenza vaccine also varies each year. A nasal spray flu vaccine is available for healthy persons aged 5 through 49 years who are not pregnant.

For More Information

Centers for Disease Control and Prevention
(800) 232-2522
www.cdc.gov

American Lung Association
(800) LUNGUSA (586-4872)
www.lungusa.org