Similarities Between the Flu and COVID-19

Fall Issue

Influenza (flu) and COVID-19 are both contagious respiratory illnesses, but they’re caused by different viruses. Because they share many of the same symptoms, it may be hard to tell the difference between the flu and COVID-19 based on symptoms alone. Testing may be needed to help confirm a diagnosis. 

Causes the same symptoms.

  • Fever or feeling feverish/chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue (tiredness)
  • Sore throat
  • Runny or stuffy nose
  • Muscle pain or body aches
  • Headache
  • Some people may have vomiting and diarrhea, though this is more common in children than adults

The CDC has a free tool that will help you assess your symptoms and seek appropriate care. To use it, visit

Same appearance of symptoms. 

For both COVID-19 and flu, 1 or more days can pass between a person becoming infected and when he or she starts to experience illness symptoms.

Spreads the same way.  

  • Spread from person-to-person, between people who are in close contact with one another (within about 6 feet).
  • Spread mainly by droplets made when people with the illness (COVID-19 or flu) cough, sneeze, or talk. 
  • Infection is possible by physical human contact (i.e. shaking hands) or by touching a surface or object that has the virus on it and then touching one’s own mouth, nose, or possibly eyes.
  • Spread to others by people before they begin showing symptoms, with very mild symptoms or who never developed symptoms (asymptomatic). It’s possible to spread the virus for a least 1 day before experiencing any symptoms.

Endangers the same high-risk population. 

Both COVID-19 and flu illness can result in severe illness and complications. Those at highest risk include:

  • Older adults
  • People with certain underlying medical conditions
  • Pregnant women

Causes the same complications

  • Pneumonia
  • Respiratory failure
  • Acute respiratory distress syndrome (i.e. fluid in lungs)
  • Sepsis
  • Cardiac injury (e.g. heart attacks and stroke)
  • Multiple-organ failure (respiratory failure, kidney failure, shock)
  • Worsening of chronic medical conditions (involving the lungs, heart, nervous system or diabetes)
  • Inflammation of the heart, brain or muscle tissues
  • Secondary bacterial infections (i.e. infections that occur in people who have already been infected with flu or COVID-19)