What is Influenza (also called the “flu”)?

Influenza, commonly called the “flu,” is caused by the influenza virus, which infects the respiratory tract (nose, throat, lungs). Unlike many other viral respiratory infections, such as the common cold, the flu can cause a more severe illness and possibly life-threatening complications.

Recognizing the signs of flu in people

You may have the flu if you have some or all of these symptoms:
• fever
• cough
• sore throat
• runny or stuffy nose
• body aches
• headache
• chills
• fatigue
• possibly vomiting or diarrhea (more likely in children)

What you can do to stay healthy:

Influenza is thought to spread mainly from person-to-person through coughing or sneezing of infected people. You can take everyday actions to stay healthy:
• Get vaccinated
• Cover your cough or sneeze
• Wash your hands often
• Avoid touching your eyes, nose, and mouth
• Stay home if you are sick

Special Populations at Increased Risk

You may be at risk for serious complications from the flu if you:
• Are 65 years or older, or 23 months and younger
• Have chronic medical conditions
• Are taking long-term immune suppressive therapy
• Are pregnant

Some complications of flu include bacterial pneumonia, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes. Children may develop sinus problems and ear infections.