Influenza, or the “flu,” is a contagious respiratory illness caused by a virus that infects the nose, throat, and sometimes the lungs.

Although symptoms in some people are mild, the flu can cause severe illness, and even death.

Older adults bear the greatest burden from the flu, according to

Compared to younger people, older adults are at higher risk for serious flu complications, including bacterial pneumonia, dehydration, and worsening of other medical conditions such as heart failure, diabetes, and lung disease.

People age 65 years and older account for 50-70 percent of flu-related hospitalizations, and for 70-90 percent of flu-related deaths.

The best way to prevent the flu is by getting a flu shot every year at the start of the flu season (early fall).

The flu is different from a cold. Cold symptoms are usually milder than flu, and people with colds are more likely to have a runny or stuffy nose than people with the flu. The flu often comes on suddenly and the symptoms are more severe.

Some common symptoms of the flu include: Fever or chills (older adults may not have a fever), cough, sore throat, runny or stuffy nose, muscle or body aches, headache, fatigue, vomiting and diarrhea (more common in children).

Stop the spread of all flu viruses with these simple precautions:

* Wash your hands often with soap and water, or with an alcohol-based hand rub, especially after coughing or sneezing, and before eating.

* Cover your mouth and nose with a tissue when you cough or sneeze. If you don’t have a tissue, use the upper part of your sleeve.

* Avoid touching your eyes, nose, and mouth.

* Avoid close contact with people who are sick.

* Stay home when you are sick.