What Are They?

Seasonal influenza (the flu) and coronavirus disease 2019 (COVID-19) are viral respiratory infections that can cause mild to severe illness. Both illnesses can cause complications that may require hospitalization, especially in older adults and people of any age with certain underlying health conditions. In some cases, the complications can even be fatal. While the illnesses share some characteristics, they are unique viruses with important differences. Here’s what you need to know about the flu and COVID-19.

How the illnesses spread

Flu viruses and the virus that causes COVID-19 are contagious, and mainly spread between people through tiny respiratory droplets when an infected person coughs, sneezes or talks. These droplets can land in the noses and mouths of people who are nearby, and possibly be inhaled into the lungs. Spread is more likely when people are in close contact with one another (within about six feet). Less often, people may become infected when they touch a surface that contains the virus and then touch their mouths, noses or possibly eyes. Note that people who are infected with the flu or COVID-19 can be contagious for days before they develop symptoms.

Symptoms to watch for

The flu and COVID-19 can each cause a variety of symptoms, ranging from mild to severe. Symptoms of the flu tend to develop within 1–4 days of exposure to the virus. With COVID-19, symptoms appear within 2–14 days after the virus enters your body. Signs of each illness include:

Flu symptoms

COVID-19 symptoms

  • Fever
  • Chills
  • Headache
  • Body aches and pains
  • Fatigue and weakness
  • Cough
  • Sore throat
  • Fever
  • Chills
  • Cough
  • Shortness of breath or trouble breathing
  • Fatigue
  • Body or muscle aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

The following are emergency signs of illness. If you have any of these symptoms, seek medical help right away:

Flu emergency warning signs

COVID-19 emergency warning signs

  • Trouble breathing or shortness of breath
  • Constant pain or pressure in the chest or abdomen
  • Persistent dizziness, confusion, inability to arouse
  • Seizures
  • Not urinating
  • Severe muscle pain
  • Severe weakness or unsteadiness
  • Fever or cough that improves but then comes back or gets worse
  • Worsening of chronic health conditions
  • Trouble breathing
  • Constant pain or pressure in the chest
  • New confusion
  • Inability to wake up or stay awake
  • Bluish lips or face

In children, emergency warning signs of the flu can also include fast breathing, bluish lips or face, ribs pulling in with each breath, chest pain, not urinating for eight or more hours, dry mouth, no tears when crying, loss of alertness or a fever over 104°F (in children younger than 12 weeks, any fever is an emergency.)

People at risk for severe illness

Anyone can become infected with the flu or COVID-19 if they are exposed to the viruses that cause these illnesses. Know that in many cases, infections are mild and people are able to recover on their own. Still, certain people have a higher risk of severe illness and complications.

Higher risk of flu complications

Higher risk of severe COVID-19 illness

  • People 65 years and older
  • Children five years and younger, especially those two years and younger
  • Pregnant women
  • People with chronic medical conditions, such as diabetesheart disease and asthma
  • People with weakened immune systems, including those with human immunodeficiency virus (HIV), acquired immunodeficiency syndrome (AIDS) or an organ transplant
  • People 65 years and older
  • People who live in a nursing home or long-term care facility
  • People with underlying medical conditions, especially if they aren’t well-controlled, such as chronic lung disease, moderate to severe asthma, serious heart issues, diabetes, liver disease and chronic kidney disease and receiving dialysis
  • People with severe obesity (a body mass index of 40 or greater)
  • People with weakened immune systems, including those who smoke, have received cancer treatment or an organ transplant or who have human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS)

Which virus do I have?

Since both infections share many of the same symptoms, it may not be possible to know which illness you have without seeing your health care provider or getting tested. If you have symptoms of the flu or COVID-19, contact your provider, especially if you are at high risk for severe infection. They may examine or test you for the flu or COVID-19. 


Most people who become infected with the flu or COVID-19 recover on their own. For mild cases, the goal of treatment is to ease symptoms. Getting enough sleep, drinking plenty of fluids and using over-the-counter medicines can temporarily relieve symptoms.

If you have the flu, your health care provider may prescribe antiviral medications. When treatment is started promptly after you start to feel sick, these medications can lessen symptoms and shorten the length of your illness by about one to two days. Antiviral medicines may also reduce the risk of flu-related complications.

At this time, there are no U.S Food and Drug Administration or FDA-approved medicines specifically for COVID-19. Scientists are learning more about the virus each day, and are working to find treatments.


According to the Centers for Disease Control and Prevention (CDC), getting the flu vaccine each year is the best way to protect yourself from the flu. Flu vaccination can prevent flu-related illnesses, health care provider visits and hospitalizations, and it can even be lifesaving in children. While there is no vaccine for COVID-19 yet, scientists are working on developing one. In thFe meantime, there are actions you can take to reduce your risk of getting sick with COVID-19 or the flu:

  • Wash your hands often. Wash your hands with soap and water for at least 20 seconds after coughing, sneezing, blowing your nose, and being in public settings. When soap and water aren’t available, use a hand sanitizer that contains at least 60% alcohol.
  • Do not touch your mouth, nose or eyes with unwashed hands.
  • Keep your distance from others. Stay at least six feet away from other people, especially those who are sick. If someone in your home is ill, try to keep your distance from them, too.

If you have either illness, it’s important to try to stop from spreading it to others. Stay home, except to get medical care, when you’re sick. Since you may be able to pass illness to others before you know you’re sick, the CDC recommends that people wear cloth face coverings that cover their noses and mouths in public settings to keep from spreading COVID-19 to others.

Published on August 1, 2020 by Jenilee Matz, MPH 


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