U-M Health Lab: Cold, Flu or COVID-19? Here’s How to Tell the Difference

This article was updated on September 16, 2021.

You wake up one morning feeling under the weather. While in previous years you may have chalked up a sore throat or body aches to a run-of-the-mill cold or flu, the ongoing COVID-19 pandemic adds a new element of concern to getting sick.

“There is significant overlap between symptoms of influenza and COVID,” said Laraine Washer, medical director of infection prevention and epidemiology at Michigan Medicine. “Both can present with fevers, chills, cough, muscle/body aches, fatigue and headache.” Here, Washer offers advice to follow during this unique cold and flu season.

Is it a cold, the flu or COVID?

Cold symptoms are mild and the common cold tends not to be associated with fever or headache.

Congestion/runny nose is common for the common cold and would be uncommon to be the only symptom for influenza. Congestion/runny nose can be a symptom of a COVID infection and might be the only symptom in mild cases.

SEE ALSO: Seeking Medical Care During COVID-19

Flu symptoms are often of rapid onset. COVID symptoms can be of rapid or more gradual onset.

Says Washer, one symptom that is more unique to a COVID infection is the loss of taste or smell. And symptoms from the delta variant are similar to prior versions of COVID.

Should I get a test?

Washer says that in many settings, the only way to tell the difference between COVID and influenza is by testing. “The differentiation can be very important as there are isolation requirements to prevent transmission of COVID and antivirals that can be used for influenza,” she explained.

If you have fever/chills, new cough or new shortness of breath, you should stay home and arrange to be tested for COVID.

If you have two or more of the following symptoms:

  • headache,
  • new muscle aches,
  • new upper respiratory symptoms (congestions, runny nose, sore throat),
  • new loss of taste or smell, new nausea/vomiting/diarrhea,
  • or new rash,

you should consider COVID testing, even if you’ve been vaccinated. If you have had a known close contact exposure to someone with COVID, you should be tested even if you have one mild symptom.  If you are a Michigan Medicine patient, you can call the COVID hotline (734-763-6336). There is a low threshold for COVID testing given risk of transmission to others.  Once influenza season begins, your doctor may also wish to test you for flu.

Should I call the doctor?

If you have any chronic medical conditions, are over the age of 65, or are not vaccinated, you are at higher risk of getting a severe COVID infection and should call your doctor. Call your doctor for a fever that does not go down with fever reducing medicine (do not use aspirin as it is contraindicated in influenza) or any severe symptoms or symptoms that get worse over time.

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Should I go to the emergency room?

Go the emergency department if you have chest pain or pressure, confusion, difficulty breathing or blue discoloration to your lips or face.

And while social distancing and masking reduced flu last year, that may not be the case this year.

Last year, “flu and other respiratory illnesses were reduced in the Southern Hemisphere, whose flu season typically stretches from May to November,” said Washer. However, there is already a moderate to high level of influenza circulating in some U.S. states, so there will likely be significantly more cases of the flu this winter compared to last year.

The flu shot and COVID vaccine

Getting a flu shot this year is particularly important to reduce the potential for a twin pandemic of influenza and COVID, which could further overwhelm the healthcare system. The flu vaccine has been updated this year to better match circulating strains. The Centers for Disease Control and Prevention recommend that you get the flu shot before the end of October, but it’s never too late to get one. Plus, if you haven’t gotten your COVID vaccine yet, you can get one at the same time as your flu shot.

Added Dr. Washer, “Continue to social distance, avoid large gatherings and wear your mask! And get and use a thermometer.”

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