Similarities and Differences between COVID-19 and Flu

By October 9, 2020Health Tips

As we get closer to flu season, many people are worried that if they or their children get sick, it may not be easy to know the difference between the flu and COVID-19.  In fact the symptoms of these two infections are very similar.  Without a test, or maybe more than one test, it may be impossible to tell for certain which one you have.  It is also possible to have both infections at the same time.  Wouldn’t that be terrible!  There are some clues that might help to tell them apart, which we will talk about today.

First and most importantly, get your flu shot!
Similarities and Differences between COVID-19 and FluWe don’t know yet what the flu season will be like this year.  If everyone is social distancing, washing their hands, and wearing masks, these measures could certainly help decrease flu transmission.  However, the stakes are high this season.  As COVID-19 cases are rising around the country, the fear of a bad flu season on top of the COVID-19 pandemic has health experts worried.  This year flu shots were made in large numbers and distributed early, just for this reason.


Please get your flu shot!  They are safe.  They are effective at preventing the flu, although not 100%.  On the off chance that you do catch the flu after getting the flu shot, you are much less likely to have a severe flu infection that leads to hospitalization or death.


How are the symptoms of COVID-19 and the flu similar?
Although both of these infections can have a wide variance in the severity of symptoms from one person to the next, here are some common symptoms that these infections share:
  • Fever and/or chills
  • Body aches
  • Cough
  • Fatigue or feeling tired
  • Sore throat
  • Runny or stuffy nose
  • Headache
  • Shortness of breath (Much more common with COVID-19, but can happen with influenza pneumonia.)
  • Vomiting and diarrhea (more common in children than adults)
What are the differences between the symptoms of the flu and COVID-19?
These are the symptoms of COVID-19 that you don’t usually see with the flu:
  • Sudden loss of the sense of smell
  • Red and/or itchy eyes
  • Redness or blisters on fingers or toes (sometimes called “COVID toes”)
  • Serious breathing difficulty
  • Pain or pressure in your chest
  • Blue lips, face, or fingertips
  • Confusion or disorientation
  • Collapsing or losing consciousness
  • People also sometimes develop pneumonia with COVID-19 without realizing how sick they are.  This can lead to a sudden turn for the worse, which seems to be out of nowhere.
Here are some other ways that COVID-19 and the flu can be different:
  • How long does it take for symptoms to appear after exposure?
    • Flu – Usually causes symptoms anywhere from 1 to 4 days after being exposed.
    • COVID-19 – Typically does not cause symptoms until 5 days after being infected, but symptoms can start as early as 2 days after, or as late as 14 days after infection.
  • How long can someone who has the virus spread it to others?
    • Flu – Most patients are contagious for about 1 day before they have symptoms, are most contagious for the first 3-4 days of illness, but may remain contagious for 7 days.
    • COVID-19 – Remember that we are still learning about how long someone can be contagious with COVID-19.  We do know that people can be contagious for about 2 days before they start having symptoms and are still contagious on average for 10 days after signs or symptoms first appear.  Some people have been contagious for much longer.  Even if someone has no symptoms or their symptoms go away quickly, they can still be contagious for at least 10 days after testing positive for COVID-19.
  • How does the virus spread?
    • Both the flu and COVID-19 can spread from person-to-person, between people who are in close contact with one another (within about 6 feet).  Both are spread mainly by droplets made when people talk, cough, or sneeze, or by physical contact.
    • Both may be spread by touching an object that has the virus on it, then touching your mouth, nose, or eyes.
    • Both may be spread by people before they have symptoms or by people who have the virus with no symptoms.
    • COVID-19 is more contagious than flu in general, especially among certain populations and age groups.
    • COVID-19 can be spread by aerosol particles, which are tiny particles that hang in the air for long periods of time and can travel farther than 6 feet.  This is especially true in enclosed spaces with poor ventilation and with activities that cause heavier breathing, like exercise or singing.  These particles can linger in the air even after the person has left the room.
  • What are the serious complications?
    • Both COVID-19 and the flu can lead to serious complications, such as pneumonia, acute respiratory distress syndrome, organ failure, heart attacks, heart inflammation (which can cause long-term congestive heart failure), brain inflammation, stroke, and death.  These complications are more likely with COVID-19.
    • COVID-19 can cause additional complications not seen with the flu, which include blood clots and Multisystem Inflammatory Syndrome in Children.
    • COVID-19 death rate is estimated to be at least 5 to 10 times higher than flu (or higher).
    • Flu causes approximately 34,000 to 43,000 deaths in the U.S. each year, most years.  Some years, when we have a particularly harsh flu season, it can be up to 62,000 deaths.
    • COVID-19 has thus far caused over 211,000 deaths in the U.S. in less than a year since the pandemic started.
  • What are the treatment options?
    • Flu – Prescription antiviral drugs are FDA-approved for treatment of the flu.
    • COVID-19 – While there are clinical trials ongoing, and there is an antiviral drug available under Emergency Use Authorization, there are currently no drugs or other therapeutics approved by the FDA to prevent or treat COVID-19.
  • Vaccines
    • Flu – There are multiple FDA-licensed vaccines for the flu produced every year to protect against the 3 or 4 flu viruses that scientists anticipate will circulate each year.
    • COVID-19 – Currently there is no vaccine to prevent COVID-19.  There is currently an expedited effort between vaccine developers, researchers, and manufacturers trying to develop an effective vaccine for COVID-19.
What should you do to prepare for the flu season?
  • Continue to practice social distancing, frequent handwashing, avoid large events and mass gathering, and absolutely wear a face covering when you are in public.
  • Get your flu shot, and take your children to get their flu shots.

If you have any questions about COVID-19 and the Flu, please log into your account and send
us your question. We are here to help.

Dr. Anita Bennett MD – Health Tip Content Editor

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