But how can you tell the difference between the flu, common cold and COVID-19?
It's a question Andres Gonzalez has heard over and over as he serves customers at Don Andres Mexican Restaurant in Hammond, Indiana.
"A lot of my customers have the flu, and they confuse it with COVID," Gonzalez said. "People cannot tell the difference because the symptoms are the same. I'm sure a lot of people confused by it."
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Doctors admit it's confusing. Symptoms are similar: body aches, fever, chills, feeling fatigued, congestion, coughing and sneezing.
Dr. Meeta Shah is an emergency physician with Rush University Medical Center.
"The symptoms are very similar, so just go get tested," Shah said. "That's your best case scenario. Obviously, getting vaccinated for both influenza and COVID is also your best chance of recovering quicker."
The CDC is tracking this year's flu season and has a Weekly Influenza Surveillance Report.
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Nationwide, October's map showed a sea of green states, which signifies low or minimize flu activity.
By November, flu cases visibly increased. For example, New Mexico went from yellow to red, reporting a high number of flu cases.
The CDC's latest surveillance map, which includes information through Dec. 18, shows more states with moderate and high cases. Indiana is in red, indicating a high level of influenza. But a spokeswoman with the Indiana state health department released a statement Wednesday, saying "there was a technical issue with the flu reports imported by the CDC, which inaccurately inflated Indiana's flu activity. Indiana's current flu activity is minimal to moderate."
A spokesman with Franciscan Health in northwest Indiana confirms they have seen a handful of flu cases that do not require hospitalizations.
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Health officials say emergency rooms should be used for emergencies only because there are other options.
"If you are feeling okay, try to use things like Tele-Health, calling your doctor's office, doing a virtual appointment there, using the testing centers that are popping up all over your communities. Those are really the ways to go," Shah said.
"Do the stuff your mom taught you to do, which is fluids, rest," she added. "If you got a fever, take some Tylenol, and use some over-the-counter cold and cough medicines."
Shah said its not too late to get a flu shot, and when Indiana starts seeing flu cases, she said Chicago is usually only a few weeks behind.
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"With Indiana kind of getting into flu season, I anticipate Chicago is quick to follow. So we are all thinking of that right now," Shah said.
At an unrelated event Wednesday, Chicago's top doctor addressed the issue this way.
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"There's no way to know whether somebody has a cold, the flu, COVID without a test. But right now, in Chicago, chances are very good its COVID until proven otherwise," said Dr. Allison Arwady of the Chicago Department of Public Health.
Back in Indiana, Gonzalez said he feels good.
"Myself, I'm healthy," he proclaimed.
And he hopes to stay that way as COVID-19 and flu cases increase.