Influenza (Flu) and COVID-19 are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 is caused by infection with a new coronavirus (called SARS-CoV-2) and flu is caused by infection with influenza viruses. Because some of the symptoms of flu and COVID-19 are similar, it may be hard to tell the difference between them based on symptoms alone, and testing may be needed to help confirm a diagnosis. Flu and COVID-19 share many characteristics, but there are some key differences between the two.
Both COVID-19 and flu can have varying degrees of signs and symptoms, ranging from no symptoms (asymptomatic) to severe symptoms. Common symptoms that COVID-19 and flu share include:
- 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
Differences:
Flu viruses can cause mild to severe illness, including common signs and symptoms listed above.
COVID-19 – other signs and symptoms of COVID-19, different from flu, may include change in or loss of taste or smell.
How long symptoms appear after exposure and infection
Similarities:
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.
Differences:
If a person has COVID-19, it could take them longer to develop symptoms than if they had flu.
Flu – Typically, a person develops symptoms anywhere from 1 to 4 days after infection.
COVID-19 – Typically, a person develops symptoms 5 days after being infected, but symptoms can appear as early as 2 days after infection or as late as 14 days after infection, and the time range can vary.
For more information on the difference of the flu and COVID-19 visit https://www.cdc.gov/flu/symptoms/flu-vs-covid19.htm