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Signs & Symptoms

Flu can cause mild to severe illness and flu symptoms can vary from person to person. Flu symptoms usually appear 1-4 days after exposure to the virus and usually include the onset of:

  • fever
  • cough
  • muscle aches and pain

Other symptoms of the flu can include:

  • headache
  • chills
  • fatigue (tiredness)
  • loss of appetite
  • sore throat
  • runny or stuffy nose

Some people, and especially children, might also have:

  • diarrhea
  • nausea and vomiting

Differences Between the Flu and COVID-19

Influenza (flu) and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses. It can be difficult to tell the difference between flu and COVID-19 because the symptoms are similar. Testing is important to confirm a diagnosis of COVID-19.

To learn more about the symptoms of COVID-19, testing and diagnosis visit:

COVID-19 Symptoms

COVID-19 Testing and Diagnosis

Differences Between the Flu and a Common Cold

Both the flu and a common cold come from respiratory tract infections in your nose, sinuses and throat. Flu is different from a common cold and most people have trouble deciding if it is the flu or a cold. The following can help you know the difference:

Symptoms Cold Flu
Fever & Chills Rare Usually
Cough Mild Common;
can be severe
Headache Rare Almost always
Stuffy Nose
Common Sometimes
Body Aches and Pains Slight Usually
Onset Gradually gets worse over a few days Comes on quickly and severely
Diarrhea/Vomiting Rare More common in children
Recovery Symptoms may last 3-10 days Symptoms may last hours or days up to a week and may linger for up to 3 weeks