Facts about Flu (Influenza)

Influenza is a respiratory 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 people 65 years and older, young children, and 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.

Who should get a seasonal flu vaccine?

  • Children younger than age 5, especially those younger than 2 years old
  • Adults aged 50 years and older, especially those 65 years and older
  • Pregnant women (and women up to 2 weeks postpartum)
  • Residents of nursing homes and other long-term care facilities
  • American Indians and Alaskan Natives
  • Health care workers
  • Household contacts and caregivers of children younger than 5 years, (especially those younger than 6 months), adults aged 65 and older, or people with high-risk medical conditions

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. in 2014, over 2000 New Yorkers died from influenza and its complications (including 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 older than 65
  • People with any of these medical conditions:
    • Asthma or any other chronic respiratory diseases
    • Heart, kidney or liver disease
    • People who are morbidly obese (BMI ≥40 kg or 88 lbs/m2)
    • Hematologic diseases, such as sickle cell anemia
    • Metabolic disorders, such as diabetes
    • Weakened immune system, from illness or medication
    • Neuromuscular disorders that interfere with breathing or the discharge of mucus
    • Long-term aspirin therapy in people under 19

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