CDC, Centers for Disease Control and Prevention

Similarities and Differences between Flu and COVID-19​

What is the difference between Influenza (Flu) and COVID-19?

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 coronavirus first identified in 2019, and flu is caused by infection with influenza viruses.

• COVID-19 seems to spread more easily than the flu. However, as more people become fully vaccinated against COVID-19, the spread of the virus that causes COVID-19 should slow down. More information is available about COVID-19 vaccines and how well they work.

• Compared to flu, COVID-19 can cause more serious illnesses in some people. COVID-19 can also take longer before people show symptoms and people can be contagious for longer. More information about the differences between flu and COVID-19 is available in the different sections below.

• Testing is needed to tell what the illness is and to confirm a diagnosis. People can be infected with both flu and the virus that causes COVID-19 at the same time and have symptoms of both influenza and COVID-19.

While more is learned every day about COVID-19 and the virus that causes it, there are still things, such as post-COVID conditions, that are unknown.

For more information visit the CDC website:  https://www.cdc.gov/flu/symptoms/flu-vs-covid19.htm