Facts about Flu (Influenza)
Printable version (PDF - December 2014)
Flu and You: Important Information for Older Adults (PDF - December 2014)
Influenza is a viral infection of the nose, throat, bronchial tubes and lungs. There are two main types of virus: influenza A and influenza B. Each type includes many different strains, which tend to change each year. Seasonal influenza sometimes causes severe illness or complications, but the great majority of people recover fully without any medical treatment.
When does influenza occur?
Influenza is most common during the fall and winter months. Influenza activity often increases during the late fall and early winter in the United States, but peak levels generally occur between late December and early March. Illnesses resembling influenza may occur during the summer months but they are usually due to other viruses.
Who gets influenza?
Anyone can get influenza, but it is most serious in the elderly, in young children, in people with chronic underlying health conditions such as asthma, diabetes or a weakened immune system.
How is influenza spread?
Influenza is highly contagious and is easily transmitted through contact with droplets from the nose and throat of an infected person during coughing and sneezing.
What are the symptoms of influenza?
Typical symptoms include fever, chills, aches, cough and sore throat. Intestinal symptoms, such as vomiting or diarrhea, are possible but uncommon. Although most people are ill for only a few days, influenza sometimes leads to more serious illness, such as pneumonia. Influenza-related illness, including pneumonia, causes death in a low of about 3,000 to a high of about 49,000 people in the United States each year. During the 2013-2014 influenza season, 1,826 New Yorkers died from influenza and pneumonia.
How soon after infection do symptoms appear?
Influenza generally occurs within 1 to 4 days after exposure.
How is influenza diagnosed?
Doctors diagnose influenza by checking for common symptoms such as fever, chills, aches, cough and sore throat. Lab tests are sometimes used to confirm the diagnosis, but these tests are not necessary or useful in most instances.
What should I do if you I get flu-like symptoms?
Most people recover from flu on their own, without medical treatment. They do not need to go to the hospital, but they do need to take steps to avoid spreading the infection. If you have a fever (100 degrees or higher), plus a cough or sore throat, be sure to take these steps:
- Stay home from work or school. Do not return until you have been free of fever for 24 hours.
- Avoid close contact with other people. Stay away from crowded public places and avoid close face-to-face contact with household members.
- Cover your nose and mouth when you cough or sneeze
- Wash your hands often.
When should I call a doctor?
Some people are more likely than others to get very sick with influenza. People who have flu-like symptoms or have had recent close contact with someone with flu-like symptoms should call a health care provider if they belong to any of these higher risk groups:
- Pregnant women
- People younger than 2 or 65 and older
- People with any of these medical conditions:
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