Influenza Fact Sheet

Influenza is a potentially life-threatening, contagious disease that is caused by a virus. When influenza attacks the lungs, the lining of the respiratory tract is damaged. The tissues temporarily become swollen and inflamed but usually heal within two or more weeks. Influenza is often complicated by pneumonia, especially in the elderly.

• Influenza and pneumonia combined are the seventh leading cause of death among all Americans and the fifth leading cause of death among all Americans over the age of 65. Influenza and pneumonia together resulted in 64,847 deaths in 2003.
• In 2004 influenza and pneumonia represented a cost of $37.5 billion to the U.S. economy, $5.6 billion due to indirect costs and $31.9 billion in direct costs.
• For healthy children and adults, influenza is typically a moderately severe illness. For unhealthy or elderly people, influenza can be very dangerous.
• In the U.S. the 2004-2005 influenza activity was moderately severe. Numerous outbreaks were reported in long-term care facilities and among school children.
• Adults 65 years of age and older who contract influenza are much more likely to have serious complications from this illness, which can affect their health and independence.
• A person can have influenza more than once because the virus that causes influenza may belong to different strains of one of three different influenza virus families, A, B, or C. Type A viruses tend to affect adults, Type B viruses tend to affect children. Both A and B have strains that cause illness of varying severity. The influenza A family has more strains than the B family.
• An emerging type A strain is the avian influenza virus or bird flu.  Bird flu viruses do not usually infect humans, but several cases of human infection with bird flu viruses have occurred since 1997 especially in Asia.  The death rate for these reported cases has been about 50 percent. The virus is mainly transmitted to humans by direct contact with live, sick or dead poultry, however, it is thought that a few cases of human-to-human spread have occurred.
• Some of the symptoms associated with influenza are: fever, bodily aches and pains, chills, sore throat/dry cough, coughing, loss of appetite, and weakness.
• SARS, a potentially more serious illness may start like the flu.  Check with your doctor immediately if complications such as difficulty breathing occur in areas where SARS is found.
• Influenza is a very serious illness for anyone at high risk. Certain diseases that place people at high risk include: chronic lung disease such as asthma, emphysema, chronic bronchitis, bronchiectasis, tuberculosis, or cystic fibrosis; heart disease; chronic kidney disease; diabetes or other chronic metabolic disorder; severe anemia; and diseases or treatments that depress immunity.
• Target populations for the flu shot include children aged 6-23 months, adults that are in close contact with children aged 6-23 months, people 50 years of age and older, healthcare workers, all care givers of high risk people and people with chronic health conditions such as asthma, as well as pregnant women.
• According to a recent American Lung Association study, the flu shot is safe for people with asthma.
• In 2004, 67.8% of U.S. adults age 65 and older received the flu shot during the preceding year.
• Influenza shots are covered by Medicare and other health insurance programs.
  Most people experience little or no reaction to the flu shot. The most common side effect is a swollen, red, tender area where the vaccination is given which affects 10 to 60 percent of patients.
• The newest option for vaccination against the flu is Flu Mist. Flu Mist is the first nasal spray vaccine for influenza and has been approved by the FDA for healthy people ages 5-49 years of age. Safety has not been proven in high-risk groups.
• The best period to receive any of the influenza vaccines is soon after the vaccine becomes available in the fall of each year.
• Two antiviral drugs, amantadine and rimantadine are useful for treating influenza A if given as soon as possible after exposure to or onset of influenza. Both drugs may be used as preventive medications, but they must be taken daily as long as influenza cases continue to occur in the community. Both may cause mild side effects.
• In addition, two new drugs, Zanamivir and Oseltamivir (neuraminidase inhibitors), one inhaled and one in pill form have been shown to reduce flu symptoms if taken at the onset of the disease. These newer drugs can be used to treat strains from both the Influenza A and B viruses. Oseltamivir can also be used to prevent influenza.
• In the US, the frequency of adamantane resistance increased from 1.9% during the 2003-04 season to 11% during the 2004-05 season. Therefore the CDC recommends that the adamantane antiviral drugs should not be used for influenza A infections for the remainder of the 2005-06 influenza season as most flu strains that season were resistant. The neuraminidase inhibitors should be used for treatment and chemoprophylaxis of influenza instead.
• Additional analysis by the American Lung Association found that if 100% of people with asthma received a flu shot, close to 136,000 hospitalizations could be prevented each year, resulting in a cost savings of $757 million.

For more information call the American Lung Association at 1-800-LUNG-USA (1-800-586-4872), or visit http://www.lungusa.org.

Sources:

National Center for Health Statistics (NCHS). Report of Final Mortality Statistics, 1979-2002. National Vital Statistics Report, Preliminary data for 2003.

Centers for Disease Control and Prevention. Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report 2003;52 (RR-8).

The American Lung Association Asthma Clinical Research Centers. The Safety of Inactivated Influenza Vaccine in Adults and Children with Asthma. New England Journal Medicine.  Vol. 345; 1529-36: November 2001.

Centers for Disease Control. Behavioral Risk Factor Surveillance System, Prevalence Report 1997-2004.

Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP) (MMWR 29 July 2005;54[RR08]:1-40).

U.S. Food and Drug Administration. Press release: "First Nasal, Mist Flu Vaccine Approved." June 17, 2003. Available at: http://www.fda.gov/bbs/topics/NEWS/2003/NEW000913.html. Accessed on 3/31/06.

Centers for Disease Control. MMWR. January 17, 2006. 55(Dispatch); 1-2. High Levels of Adamantane Resistance Among Influenza A (H3N2) Viruses and Interim Guidelines for Use of Antiviral Agents-US, 2005-06 Influenza Season.

National Institute of Allergy and Infectious Disease, Flu Drugs Fact Sheet, January 2006.

Centers for Disease Control. MMWR. January 17, 2006. 55(Dispatch); 1-2. High Levels of Adamantane Resistance Among Influenza A (H3N2) Viruses and Interim Guidelines for Use of Antiviral Agents-US, 2005-06 Influenza Season.

The American Lung Association Asthma Clinical Research Centers. The Safety of Inactivated Influenza Vaccine in Adults and Children with Asthma. New England Journal Medicine.  Vol. 345; 1529-36: November 2001.