Signs and Symptoms

The flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat and lungs. Though the flu and a cold share many symptoms, they cannot be treated alike. A cold is caused by a different virus and has milder symptoms, while the flu can cause mild to severe illness, and at times lead to death.

Common signs and symptoms of the flu virus include:

  • Fever* or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)
  • Some people may experience diarrhea and vomiting, though this is more common in children than in adults.

*It’s important to note that not everyone with the flu has a fever.