Is It COVID-19 or the Flu? Here’s How to Tell Them Apart, According to Doctors

The novel coronavirus and influenza are similar, but they have a few key differences.

Nobody loves coming down with a nasty case of the flu. Compared to your typical cold, influenza can really wipe you out, leading to a high fever, deep chest coughs, overwhelming fatigue, and uncomfortable body aches all over.

But this year’s flu season presents a unique challenge as the novel coronavirus continues to spread throughout the U.S. Many states are expecting a “second wave” of COVID-19 this fall and winter (even though a majority of the country never really flattened its first uptick in cases).

Both the flu and COVID-19 are expected to put a strain on our healthcare system during the colder months, and unfortunately, it’s difficult to tell the two apart because the symptoms can be nearly identical. “Both influenza and coronavirus are very dangerous,” says Rajeev Fernando, M.D., an infectious disease expert in Southampton, New York. “We have to be careful and concerned about both of them.”

Here’s what doctors know about how COVID-19 compares to the flu so far, which symptoms may present differently, and how to stay healthy.

COVID-19 symptoms vs. flu symptoms

sick woman in bed with thermometer

(Image credit: Thomas_EyeDesign)

There’s a lot of overlap in symptoms between these two illnesses. But these are the main symptoms of COVID-19 to keep on your radar, according to the Centers for Disease Control and Prevention (CDC):

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

Symptoms can appear between two and 14 days after a person is infected, the CDC says.

The CDC lists these as the major symptoms of the flu:

  • Fever or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)
  • Some people may have vomiting and diarrhea (although it’s more common in children than adults)

The flu comes on fast, typically one to four days after you have been infected. Keep in mind that not everyone with the flu develops a fever, but it is still common.

While both the flu and COVID-19 are believed to spread from person-to-person via respiratory droplets after a person talks, coughs, or sneezes, the CDC says COVID-19 is more contagious and has established more “super-spreading” events.

How do you know if your symptoms are due to COVID-19 or the flu?

It’s really difficult to tell the difference between the two, even for doctors. “The early symptoms of influenza and COVID can be identical,” Dr. Fernando says.

However, losing your senses of taste or smell seems to be more common with SARS-CoV-2, the virus that causes COVID-19, says Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York. “I would be much more likely to think COVID-19 than the flu if someone had that symptom,” he says. “But there’s no absolute symptom that differentiates the two.”

Only testing someone for the flu and COVID-19 can accurately determine the illness they are dealing with, says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. “Without a test, we just don’t know for sure,” he says.

Is COVID-19 more deadly than the flu?

It’s important to note that both COVID-19 and the flu are dangerous illnesses. According to preliminary data from the CDC, anywhere between 24,000 to 62,000 people died of the flu during the 2019-2020 season. CDC data also found that, as of Sept. 25, more than 190,000 Americans have died of COVID-19.

Based on these numbers alone, COVID-19 is currently more deadly than the flu. “There’s no question: COVID-19 is more dangerous than the flu in terms of lethality,” Dr. Russo says. “Our defenses to COVID-19 are really minimal when compared to influenza, which most people have been exposed to already.”

“There’s no question: COVID-19 is more dangerous than the flu in terms of lethality.”

While Dr. Fernando points out that “both viruses can cause death,”—especially in high-risk groups, like the elderly and those with underlying conditions—it is important to note that we do have one major defender against the flu: a vaccine. Even though the flu shot is not always 100% effective, it can help a person be less contagious and less sick if they do come down with a case, minimizing the risk of severe side effects.

With the flu, healthy people usually don’t have trouble recovering. Those in higher-risk groups may develop complications, including sinus or ear infections, pneumonia, bronchitis, sepsis, lung damage, and more—some of which can be deadly.

But with COVID-19, even healthy people have reported having a hard time recovering. Certain coronavirus patients, dubbed as “long haulers,” may experience symptoms for months after “recovering” from the virus. Complications can include those that come with the flu, but have also proven to be more severe in certain cases and may include heart problems and blood clots.

How are COVID-19 and the flu treated?

For mild cases of both illnesses, doctors recommend supportive care if you’re not hospitalized. That means staying home, getting plenty of rest, drinking lots of fluids, and taking fever reducing medications like Tylenol until your symptoms start to improve. Most COVID-19 patients can end isolation if it’s been 10 days after their symptoms started and 24 hours since they needed fever-reducing meds, per the CDC.

As of now, there is no “official” treatment for COVID-19 cases that become more complicated. However, doctors will typically will treat hospitalized patients with the steroid dexamethasone and anti-viral drug remdesivir, Dr. Schaffner says, adding that those are not given to people who are not hospitalized.

The flu is generally treated with antiviral drugs to help make the course of illness milder and shorten the time you are sick, the CDC says. Those medications include: oseltamivir (Tamiflu), zanamivir (Relenza), peramivir (Rapivab), and baloxavir marboxil (Xofluza).

How to protect yourself from getting sick

Experts stress the importance of getting your flu shot. “The first thing to do is to get vaccinated,” Dr. Schaffner stresses. The CDC recommends that everyone over the age of six months get a flu shot by the end of October, so your body has enough time to build up immunity to the circulating strains.

Other than that, he recommends continuing all of the things you should already be doing to prevent the spread of COVID-19 in your area. “These things will protect not only against COVID-19, but also against influenza,” Dr. Schaffner says. That includes the following:

  • Social distancing from people outside of your household
  • Wearing a face mask in public
  • Washing your hands for at least 20 seconds frequently
  • Using hand sanitizer with at least 60% alcohol when you’re in a pinch
  • Disinfecting high-touch surfaces in your home
  • Covering a sneeze or cough with a tissue
  • Avoiding unnecessary travel
  • Avoiding large gatherings
  • Seeing a doctor if you develop symptoms
Korin Miller

Korin Miller is a freelance writer specializing in general wellness, sexual health and relationships, and lifestyle trends, with work appearing in Men’s Health, Women’s Health, Self, Glamour, and more. She has a master’s degree from American University, lives by the beach, and hopes to own a teacup pig and taco truck one day.