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Is it COVID-19 or Flu? How to Know

Last updated: October 6, 2022

You can’t tell the difference between flu and COVID-19 by looking at the symptoms alone. This is why testing is needed to tell which illness you have and to confirm the proper diagnosis, needed treatment and protective practices indicated.

Dr. Suzanne Nadra Nouri Havican, ThedaCare Physicians-New London

Feeling sick is no picnic and when it’s hard to tell exactly what you have, it makes you downright miserable. A prime example of this is seasonal flu and COVID-19. With many shared symptoms between the two, it can be confusing to determine which one is making you feel sick. 

“You can’t tell the difference between flu and COVID-19 by looking at the symptoms alone,” says Dr. Suzanne Nadra Nouri Havican of ThedaCare Physicians-New London. “This is why testing is needed to tell which illness you have and to confirm the proper diagnosis, needed treatment and protective practices indicated. Testing is also important because it can reveal if you have both flu and COVID-19 at the same time.” 

Symptoms shared by COVID-19 and the flu include: 

  • Fever/chills 
  • Cough 
  • Shortness of breath or difficulty breathing 
  • Fatigue (tiredness)  
  • Sore throat 
  • Runny or stuffy nose 
  • Muscle pain or body aches 
  • Headache 
  • Vomiting 
  • Diarrhea 
  • Change in or loss of taste or smell, although this is more frequent with COVID-19 

Exposure and Spread of Infection 

According to the Centers for Disease Control and Prevention (CDC), one difference between COVID-19 and the flu is people with flu typically experience symptoms between one and four days after infection. With COVID-19, people usually develop symptoms between two and 14 days after infection. 

With both COVID-19 and flu, it’s possible to spread the virus for at least one day before experiencing symptoms, but with COVID-19, people remain contagious for a longer time period.  

Both COVID-19 and flu can spread from person to person between those in close contact with each other (within about 6 feet). Both are spread when people with the illness cough, sneeze or talk. 

Though COVID-19 and flu are spread mostly through inhalation, it may be possible to get infected by touching another person, surface or object that has virus on it, and then touching your own mouth, nose or eyes, the CDC states. 

COVID-19 is generally more contagious than flu viruses and has been linked to more “super-spreader events” than flu, meaning it can spread quickly and easily to many people, the CDC states. 

Risks and Complications 

Many people will recover from COVID-19 or the flu on their own. However, both COVID-19 and flu can lead to severe illness and complications, including pneumonia, respiratory failure, heart problems, inflammation of the heart, brain or muscle tissues, and other infections. 

COVID-19 complications can include blood clots in the arteries of the lungs, heart, legs or brain as well as Multisystem Inflammatory Syndrome, which can affect children or adults.  

Individuals can also develop post-COVID-19 syndrome, often called “long COVID,” even if they became only mildly ill or had no symptoms. Long COVID may bring a range of symptoms that can last for weeks, months or years after first being infected and can appear as early as weeks after infection. Dr. Havican says she has treated patients for long COVID, and it can be a difficult journey back to your baseline health. 

When to Seek Care 

“In this case the best defense is a good offense, and the best offense is to get vaccinated and boosted,” Dr. Havican says. “Vaccination doesn’t prevent all infections, but it can reduce the severity of illness and decrease chances of complications. As a bonus, vaccinations protect your loved ones by helping to stop the spread of illness.” 

Getting vaccinated also protects you from spreading the virus when you might not even know you have it, Dr. Havican adds. Not everyone who’s infected shows symptoms. 

Many people who develop symptoms now do COVID-19 home tests. The tests are widely available and sometimes reimbursable through insurance companies. Learn more. You can also use the COVID-19 Symptom Checker on MyThedaCare for guidance on testing and care. 

If you test positive for COVID-19, the CDC guidelines call for staying home for five days and isolating from others in your home. If you’re fever-free after five days, you may end isolation but should wear a mask around others — including those in your home — for an additional five days.  

“It’s important for you to monitor and treat your symptoms at home and to follow isolation guidelines if you have flu or COVID-19,” Dr. Havican says. “If you’re experiencing severe symptoms, please seek care for your health and the health of others.” 

ThedaCare offers both in-person and virtual care for those experiencing COVID-19 and flu symptoms. You can make an appointment with your provider, visit an urgent care or walk-in care site, or receive care through a video visit or eVisit. 

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Tags: COVID-19 Dr. Suzanne Havican flu influenza symptoms

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