Influenza (flu) and COVID-19

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Page Last Updated 7/29/24 at 3:30 pm

Influenza (flu) and COVID-10 are both contagious respiratory illnesses, but they are caused by different viruses. COVID-19 is caused by an infection with a coronavirus (SARS-CoV-2) first identified in 2019. Flu is caused by infection with an influenza virus (CDC, 2024).

Both COVID-19 and flu share many signs and symptoms, testing is the only way to confirm which virus you may have.  Early testing, diagnosis, and treatment leads to less chance of spreading the virus and a quicker recovery, helping to reduce the chances of getting very sick. Sometimes, but not very often, you may have both COVID-19 and the flu at the same time.  This can lead to more severe disease than having just one of the viruses on their own.

 

Please click here for information about free or discounted COVID-19 care.

 

What symptoms may be the same?

Fever or feeling feverish/having chills (Not everyone with flu will have a fever.)

Cough

Shortness of breath or difficulty breathing

Fatigue (tiredness)

Sore throat

Runny or stuffy nose

Muscle pain or body aches

Headache

Vomiting

Diarrhea (more frequent in children with flu, but can occur in any age with COVID-19)

Change in or loss of taste or smell, although this is more frequent with COVID-19.

 

It is possible to be infected with either virus and not experience any symptoms.

 

Both can result in severe illness, those at increased risk include:

Older adults

People who are pregnant

People with certain underlying medical conditions (including infants and children)

 

Both can result in complications, including:

Pneumonia

Respiratory failure

Acute respiratory distress syndrome (fluid in the lungs)

Sepsis (a life-threatening illness caused by the body’s extreme response to an infection)

Cardiac injury (for example, heart attacks and stroke)

Multiple-organ failure (respiratory failure, kidney failure, shock)

Worsening of chronic medical conditions (involving the lungs, heart, or nervous system or diabetes)

Inflammation of the heart, brain, or muscle tissues

Secondary infections (bacterial or fungal infections that can occur in people with flu or COVID-19)                                                   

What is different?

Influenza (Flu)

May experience symptoms anywhere from one to four days after infection.

Most recover in a few days to two weeks.

Diarrhea is more common in young children with flu than in adults with flu.

COVID-19

Spreads more easily from person to person

May experience symptoms anywhere from two to five days, and up to 14 days after infection.

May be contagious for longer periods of time.

Seems to cause more severe illness in some people.

Additional complications associated with COVID-19 can include:

Blood clots in the veins and arteries of the lungs, heart, legs or brain

Multisystem Inflammatory Syndrome in Children (MIS-C) and in Adults (MIS-A)

 

Anyone who has had COVID-19, even if their illness was mild, or if they had no symptoms can experience post-COVID conditions. These are long-term effects from their infection, it may also be referred to as long-haul COVID, post-acute COVID-19, long-term effects of COVID, and chronic COVID. The term post-acute sequelae of SARS CoV-2 infection (PASC) is also used to refer to a subset of Long COVID. Find more information about Post-COVID Conditions here.

 

Supporting Documents

PDF icon How to access COVID-19 treatment - Free or discounted COVID-19 care is available. (182 KB)