What is influenza?

Influenza is a respiratory infection caused by a virus (germ). Influenza occurs most often during the winter and easily spreads from person to person. The "flu season" starts in December and usually lasts until spring.

Fever, shaking chills, and shortness of breath are signs that influenza is getting worse.

Most people who get influenza feel sick for a week or two and recover. In some people, influenza leads to more serious lung infections.

What are the symptoms of influenza?

  • Moderate to high fever
  • Dry cough
  • Headache
  • Sore throat
  • Chills
  • Runny nose
  • Loss of appetite
  • Muscle aches
  • Tiredness

Many conditions — such as a common cold, diarrhea, and vomiting — are called "the flu," but are not influenza.

How can I tell the difference between a common cold and influenza?

Many cold and influenza symptoms are similar. Both common cold and influenza are caused by viruses. There are some differences with influenza. Symptoms of influenza often hit suddenly and cause you to become weaker and weaker. The dry cough and fatigue of influenza can last two to three weeks.

Signs that influenza is getting worse include fever, shaking chills, and shortness of breath.

If you think that your illness is getting worse, contact your healthcare provider promptly.