What's the difference between COVID-19 and the flu?

COVID-19 and the flu have several differences, including different causes, complications and treatments. COVID-19 and the flu also spread differently, have different severity levels and a few different symptoms, and can be prevented by different vaccines.

COVID-19 and flu causes

COVID-19 and the flu have several differences. COVID-19 and the flu are caused by different viruses. COVID-19 is caused by a new coronavirus called SARS-CoV-2, while influenza is caused by influenza A and B viruses.

COVID-19 and flu symptoms

Symptoms of COVID-19 and the flu appear at different times and have some differences. COVID-19 symptoms generally appear 2-14 days after exposure. Flu symptoms usually appear about 1-4 days after exposure.

COVID-19 and flu spread and severity

COVID-19 appears to be more contagious and to spread more quickly than the flu. With COVID-19, you may experience loss of taste or smell. Severe illness such as lung injury is more frequent with COVID-19 than with influenza. The mortality rate also is higher with COVID-19 than the flu.

So far, more than 38 million people have had COVID-19 in the U.S. as reported by the Centers for Disease Control and Prevention (CDC). More than 630,000 people have died of COVID-19 in the U.S. in 2020 and 2021.

By comparison, during the 2019-2020 flu season in the U.S., about 38 million people had the flu and about 22,000 people died of the flu.

COVID-19 and flu complications

COVID-19 can cause different complications from the flu, such as blood clots and multisystem inflammatory syndrome in children.

COVID-19 and flu treatments

Another difference is that the flu can be treated with antiviral drugs. Only one antiviral drug, called remdesivir, is currently approved to treat COVID-19. Researchers are evaluating many drugs and treatments for COVID-19. Some drugs may help reduce the severity of COVID-19.

COVID-19 and flu prevention

You can get an annual flu vaccine to help reduce your risk of the flu. The flu vaccine can also reduce the severity of the flu and the risk of serious complications. Each year's flu vaccine provides protection from the three or four influenza viruses that are expected to be the most common during that year's flu season. The vaccine can be given as a shot (injection) or as a nasal spray.

The flu vaccine doesn't prevent you from getting COVID-19. Some research has found getting a flu vaccine might lower the risk of getting COVID-19. Research also shows that getting the flu vaccine does not make you more likely to get COVID-19 or other respiratory infections.

The U.S. Food and Drug Administration (FDA) has given emergency use authorization to some COVID-19 vaccines in the U.S., and one vaccine has been approved. A vaccine can prevent you from getting the COVID-19 virus or prevent you from becoming seriously ill if you get the COVID-19 virus. Getting a COVID-19 vaccine will also allow you to start doing many things that you might not have been able to do because of the pandemic, including not wearing a mask or social distancing — except where required by a rule or law.