Those at highest risk for complications of influenza include:

• Everybody over 65 years of age.
• People with chronic heart, lung, or metabolic disorders (including diabetes).
• Those with anemia or kidney problems or whose immune systems
  aren't working properly.
• Residents of nursing homes and other chronic-care facilities.
• Children who are on long-term aspirin therapy and therefore may be
  at risk of developing a rare but very serious illness called Reye's syndrome
  following influenza infection.
• Children 6 months or older with chronic respiratory disorders.

If you get the flu you should rest in bed, drink plenty of fluids, and take medications such as aspirin or acetaminophen to relieve fever and discomfort. Children with flu should not be given aspirin without consulting a doctor because of the risk of Reye's syndrome.

Flu symptoms differ in several ways from the common cold, which is caused by different kinds of viruses. A chart illustrating those differences follows.