Flu, also called influenza, is a viral infection of the upper airways. It is usually more severe than the common cold, although it may appear like the common cold in the early stages. Typical symptoms include some or all of these symptoms: high fever, cough, sneezing, muscle aches, runny/blocked nose ...

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Introduction: Flu

Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness. Serious outcomes of flu infection can result in hospitalization or death. Some people, such as older people, young children, and people with ...1

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Symptoms of Flu

The symptoms of flu are somewhat similar to the symptoms of a common cold, but may come on more suddenly, and are often more severe. However, some cases of flu can also be mild. Typical symptoms may include some of ...

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Symptoms of Flu

Seasonal Flu

Source: NIH News in Health (NIH)2 ...

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Complications: Flu

The flu itself can be a serious illness with severe symptoms. Some people require hospitalization and fatality is possible from flu, especially in young children, the elderly, or people with other chronic diseases. The list of at-risk patients includes ...

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Complications of Flu

Bronchitis, pneumonia; can be life-threatening ...Source: NIH News in Health (NIH)3 ...

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Causes List for Flu

Some possible causes of Flu or similar disorders may include:4

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Types of Flu

“Seasonal flus change slightly from year to year,” explains Dr. Anthony S. Fauci, director of NIH’s National Institute of Allergy and Infectious Diseases. Once your immune system encounters a virus, it learns to recognize and block it, so it ...5

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Diagnosis of Flu

Influenza Diagnosis: Currently, most influenza strains go undiagnosed or are identified in a laboratory miles from a doctor’s office. If the strain is diagnosed, the time between a throat swab and a final read out can be days, if ...6

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Risk Factors for Flu

Some of the groups at greater risk include the following:

  • Children younger than 5, but especially children younger than 2 years old
  • Adults 65 years of age and older
  • Pregnant women (and women up to two weeks postpartum)
  • Residents of ...
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Misdiagnosis: Flu

Undiagnosed flu: Influenza is often undiagnosed, because it is misdiagnosed by the patient as something milder, such as the common cold. It is very important to consider Flu as a possible diagnosis, because it can be very severe, even fatal ...

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Treatments: Flu

To treat colds or flu, get plenty of rest and drink lots of fluids. If you have the flu, pain relievers such as aspirin, acetaminophen, or ibuprofen can reduce fever or aches. Allergies can be treated with antihistamines or decongestants ...7

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Prevention: Flu

The risk of contracting flu can be reduced by practical measures to avoid contagion and by the flu vaccine. Getting vaccinated with the flu is the most effective measure. Unfortunately, the vaccination does not last as long as some other ...

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Research for Flu

In addition to seasonal influenza, NIAID is also working to prepare for a potential pandemic flu threat. Pandemic flu occurs when a new flu virus strain emerges for which humans have little to no immunity, which enables the virus to ...8

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  1. Source: CDC: cdc.gov/ flu/ about/ disease/ index.htm
  2. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ issue/ oct2014/ feature2
  3. ibid.
  4. Source: Algorithmically Generated List
  5. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ 2009/ December/ feature1.htm
  6. Source: NIAID (NIH): niaid.nih.gov/ diseases-conditions/ influenza-diagnosis
  7. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ issue/ oct2014/ feature2
  8. Source: NIAID (NIH): niaid.nih.gov/ diseases-conditions/ influenza

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.