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 virus. 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. While more is learned every day, there is still a lot that is unknown about COVID-19 and the virus that causes it.

Signs and Symptoms:

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

Influenza: People with influenza have a wide range of symptoms reporting and can cause mild to severe illness and at times can lead to death.  Flu is different from a cold.  Flu usually comes on suddenly, typically 1 to 4 days after infection.

• fever* or feeling feverish/chills
• cough
• sore throat
• runny or stuffy nose
• muscle or body aches
• headaches
• fatigue (tiredness)
• some people may have vomiting and diarrhea, though this is more common in children than adults.

*It’s important to note that not everyone with flu will have a fever.

COVID 19: People with COVID-19 have had a wide range of symptoms reported – ranging from mild symptoms to severe illness. Symptoms may appear 2-14 days after exposure to the virus. People with these symptoms may have COVID-19:

• Fever or chills
• Cough
• Shortness of breath or difficulty breathing
• Fatigue
• Muscle or body aches
• Headache
• New loss of taste or smell
• Sore throat
• Congestion or runny nose
• Nausea or vomiting
• Diarrhea

This list does not include all possible symptoms. CDC will continue to update this list as we learn more about COVID-19.

Will there be flu along with COVID-19 in the fall and winter? While it’s not possible to say with certainty what will happen in the fall and winter, CDC believes it’s likely that flu viruses and the virus that causes COVID-19 will both be spreading. In this context, getting a flu vaccine will be more important than ever. CDC recommends that all people 6 months and older get a yearly flu vaccine.

Can I have flu and COVID-19 at the same time? Yes. It is possible have flu (as well as other respiratory illnesses) and COVID-19 at the same time. Experts are still studying how common this can be.

Is COVID-19 more dangerous than flu? Flu and COVID-19 can both result in serious illness, including illness resulting in hospitalization or death. While there is still much to learn about COVID-19, at this time, it does seem as if COVID-19 is more deadly than seasonal influenza; however, it is too early to draw any conclusions from the current data. This may change as we learn more about the number of people who are infected who have mild illnesses.

Why should people get vaccinated against flu? Influenza is a potentially serious disease that can lead to hospitalization and sometimes even death. Every flu season is different, and influenza infection can affect people differently, but millions of people get flu every year, hundreds of thousands of people are hospitalized and thousands to tens of thousands of people die from flu-related causes every year. An annual seasonal flu vaccine is the best way to help protect against flu. Vaccination has been shown to have many benefits including reducing the risk of flu illnesses, hospitalizations and even the risk of flu-related death in children.

 Will a flu vaccine protect me against COVID-19? Getting a flu vaccine will not protect against COVID-19, however flu vaccination has many other important benefits. Flu vaccines have been shown to reduce the risk of flu illness, hospitalization and death. Getting a flu vaccine this fall will be more important than ever, not only to reduce your risk from flu but also to help conserve potentially scarce health care resources.

Do we need to get a flu vaccine earlier this year (i.e. July/August)?  While the Advisory Committee on Immunization Practices (ACIP) has not yet voted on the flu vaccine recommendations for 2020-2021, CDC does not anticipate a major change in the recommendation on timing of vaccination. Getting vaccinated in July or August is too early, especially for older people, because of the likelihood of reduced protection against flu infection later in the flu season. September and October are good times to get vaccinated. However, as long as flu viruses are circulating, vaccination should continue, even in January or later.