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.

more severe and last longer than those of the cold.

Recovery takes about one to two weeks. Influenza can be deadly, especially for the weak, old or chronically ill.

Most people who get influenza will recover in one to two weeks, but others will develop life-threatening complications (such as pneumonia). Millions of people in the United States (about 10% to 20% of U.S. residents) are infected with influenza each year.

influenza A

Influenza is an extremely variable disease; similar viruses are found in pigs and domestic fowl.

It is possible to get vaccinated against influenza

People at high risk for complications from the flu; People 65 years and older; People who live in nursing homes and other long-term care facilities that house those with long-term illnesses; Adults and children 6 months and older with chronic heart or lung conditions, including asthma; Adults and children 6 months and older who needed regular medical care or were in a hospital during the previous year because of a metabolic disease (like diabetes), chronic kidney disease, or weakened immune system (including immune system problems caused by medicines or by infection with human immunodeficiency virus [HIV/AIDS]); Children 6 months to 18 years of age who are on long-term aspirin therapy. (Children given aspirin while they have influenza are at risk of Reye syndrome.); Women who will be pregnant during the influenza season; and All children 6 to 23 months of age.

There are some people who should not be vaccinated. This includes: 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-Barré syndrome (GBS) within 6 weeks of getting an influenza vaccine previously.

Children less

People who are sick with a fever. (These people can get vaccinated once their symptoms lessen.)

C infection usually causes either a very mild respiratory illness or no symptoms at all

Efforts to control the impact of influenza are aimed at types A an

Influenza viruses continually change over time, usually by mutation

A host infected with influenza virus develops antibodies against that virus; as the virus changes, the "first" antibody no longer recognizes the "newer" virus and infection can occur because the host does not recognize the new flu virus as a problem until the infection is well under way.

Type A viruses are divided into subtypes or strains based on differences in two viral surface proteins called the hemagglutinin (H) and the neuraminidase (N)