Influenza, also known as the flu, is a respiratory infection caused by a virus. The virus spreads through close contact with someone who is sneezing or coughing or by handling objects that were touched by someone with the flu. Compared to a cold, flu symptoms develop much faster and are more severe. They can last from 3 days to 2 weeks. Symptoms of flu include: * chills and fever * severe muscle aches * severe headache * runny nose * dry cough * sore throat Your healthcare provider can prescribe medications to reduce the severity of flu symptoms, if taken right away. You can reduce your chances of getting the flu by staying away from people who are sick; washing your hands frequently, especially before touching your eyes, nose, or mouth; and getting a flu vaccination each year.