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Flu in Adults (cont.)

What Is the Duration of Flu in Adults?

The illness from uncomplicated flu lasts from three to seven days in most adults. Cough and malaise (feeling tired or weak) can last up to two weeks following illness. Complications such as pneumonia can occur in some cases, which causes a more prolonged illness.

What Is the Contagious Period for Flu in Adults?

  • A person with flu is contagious for up to seven days after the onset of the illness, although the virus can be detected in the secretions up to 24 hours before the onset of symptoms. Thus, an individual can transmit the virus one day before symptoms begin.
  • In young children, the virus can still be spread in body secretions into the second week of illness.
  • To avoid spreading the illness, the U.S. Centers for Disease Control and Prevention (CDC) recommends that people stay home until 24 hours after the fever is gone without using fever reducers, except to obtain necessities or to seek medical care.

How Do Health Care Professionals Diagnose Flu in Adults?

In most cases, diagnosis of the flu is determined by the symptoms, especially when these occur during the peak flu season. Sometimes, the doctor may need to perform special tests to be sure the influenza virus is responsible for the symptoms and not one of the many other viruses that circulate at the same time. If an influenza virus test is positive, medication may be helpful.

A sample is taken from the back of the throat or nose. To take a sample, the doctor uses a long sterile swab and rubs the tip at the back of the throat or inside the nose. The swab is sealed in a packet for transporting specimens and sent to a lab. Some offices may use a rapid test that can be performed in the office with the result available in 30 minutes. Some rapid tests detect only influenza A virus, while others can detect both influenza A and influenza B. Some cases of the flu may be missed by the rapid tests.

Medically Reviewed by a Doctor on 10/24/2017

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