Is It Flu or COVID-19? Here's What To Expect if You Get Sick

In the United States, influenza typically peaks mid-winter. Millions (if not tens of millions) of people get sick with "the flu" each year. If their symptoms are severe, they will seek medical treatment, which could include getting a test to determine that they truly have the flu (as opposed to a bacterial infection or another virus) or asking their healthcare provider about treatment.

However, this year isn’t like any other flu season. Healthcare professionals and patients are bracing themselves for the unexpected. Some have predicted we'll have an extremely mild flu season (as the southern hemisphere experienced this year) while others have projected we'll endure a “twindemic" with COVID-19.

The latter represents a serious and unprecedented reality, with the sickest patients vying for healthcare resources. As the two infections co-mingle in the population, one of the first—and most important—tasks is to figure out which patients have the flu, which patients have COVID-19, and which patients might get both.

Symptoms

During a typical flu season, most people would not hesitate to make an appointment with their provider's office or clinic to have a test to determine which common winter illness they have—the flu, strep throat, or a bad cold.

This year, patients can add COVID-19 to the list of possibilities. However, it won't necessarily be as straightforward for people to get a diagnosis of COVID-19. There are several reasons, the foremost of which being that people might be more hesitant to leave home to get tested. Even if they are willing to risk exposure to be tested, it's not easy for everyone who is wondering if they have COVID-19 to be tested.

The flu and COVID-19 are caused by different respiratory viruses but their symptoms are similar. The symptoms of each infection also exist on a spectrum from mild to severe.

According to Jacqueline Winfield Fincher, MD, president of the American College of Physicians, the most common symptoms of both viruses are congestion, a runny nose, and a sore or scratchy throat.

You might also have a fever, body aches, fatigue, or chills. Some people (especially kids) can have gastrointestinal symptoms like nausea, vomiting, and diarrhea.

While the infections can look (and feel) similar at first glance, there are a few clues that would point toward a COVID-19 infection rather than influenza. “With COVID, we see more shortness of breath,” says Stanley Fineman, MD, a spokesperson for the American College of Allergy, Asthma, and Immunology.

The symptoms of the flu and COVID-19 also appear on different time frames. If you have the flu, you usually develop symptoms one to four days after you’ve been infected. With, COVID it usually takes five days, but symptoms can emerge anywhere from two days to as late as 14 days after infection.

“You don’t have to make these decisions on your own,” Fincher says. To find out what you have for sure—and what to do about it—the best thing you can do is call your provider.

If it's outside the office's normal business hours, you should still call. Usually, a covering physician or nurse will be on call, and that person can determine whether you need to seek immediate care (such as going to the local emergency room) or simply stay home and rest up.

When to Seek Emergency Care

If you have certain symptoms you should not wait to seek medical care. Call 911 or go to the nearest hospital if you are having trouble breathing or have chest pain or pressure that doesn’t go away.

You also need to seek emergency medical care if you are experiencing:

• A blueish tint to your face or lips
• Cough that goes away and then comes back or gets worse
• Confusion
• Dizziness
• Difficulty being woken up from sleep or staying awake
• Difficulty urinating
• Seizures or loss of consciousness
• You have a chronic medical condition that is getting worse

If you have a mild case of either virus, the best thing you can do for yourself is rest. The most important thing you can do for others is to keep your distance to prevent the spread of the virus.

“Try to reduce your contact with your family, and use a separate bathroom and bedroom if you can,” says Fincher, who is also a partner at the Center for Primary Care, McDuffie Medical, in Thompson, Georgia.

In addition to getting plenty of rest, Fincher says that staying hydrated is key to recovering. You want to drink enough fluid to have diluted (not dark) urine. You should be urinating every two to three hours.

Even if no one in your family is currently ill, it can help to stock up on supplies to make sure that you're prepared if and when it happens. Electrolyte drinks (such as Gatorade), cans of chicken soup, and saltine crackers, are all good things to have on hand during flu season, but especially in the midst of the COVID-19 pandemic when you want to leave your home as little as possible.

Testing

In a regular flu season, if you’re feeling feverish, your provider might consider your symptoms—such as sudden chills, congestion, a cough—and diagnose you with the flu. If you connect with your provider within 48 hours of the onset of symptoms, they might give you a prescription for an antiviral drug (such as Tamiflu).

This year, testing will be more crucial to differentiate between a case of the flu and a case of COVID-19. Rather than assuming that you have the flu, your provider might want you to be tested for both flu and COVID-19 (especially if you have a fever, cough, and shortness of breath).

So far this year, the Food and Drug Administration (FDA) has issued an emergency use authorization for six combination diagnostic tests for flu and COVID-19. As the flu season progresses, pharmaceutical companies expect to expand the number of testing sites.

Combination Test for COVID-19

The new tests allow providers to test for the flu and COVID-19 at the same time. Both patients and healthcare providers benefit from simultaneous testing: patients don't have to endure the unpleasant swabbing up the nose twice and they will get both results at the same time.

Swab Test for COVID-19

If your clinic doesn’t provide a combination test, your provider will swab your nose twice—once to provide a sample for the COVID-19 test, and once for the flu test. The samples will be collected in different tubes. The turnaround for results can be quick, depending on the type of test administered and your provider’s protocol.

As of October, the FDA has authorized 265 different tests under emergency approval to test for COVID-19. There are two main diagnostic tests for COVID-19—both of which can show if you have an active coronavirus infection (this is different from an antibody test, which can only tell you if you’ve been infected in the past).

A molecular test can detect a virus’s genetic material. While it's quite accurate, it can take a day or as long as a week to get results back. An antigen test—which targets specific proteins on a viral surface—can take as little as an hour but is prone to false negatives.

Influenza Tests

To test for the flu, the rapid influenza diagnostic test (RIDT) is used. The test can take less than 15 minutes, though it’s prone to false-negative results. A rapid molecular assay has higher sensitivity (90% to 95%) but takes 15 to 30 minutes to yield results.

There is a range of other more-accurate and sensitive tests available, but these tests often require several hours’ turnaround time and the use of an outside lab.

Treatment

If it turns out you do indeed have the flu, and the diagnosis is made within 48 hours, an antiviral drug (such as Tamiflu) can cut the illness short by about a day. “That’s significant if you think about it in terms of one missed day of work,” Fincher says. Household members can also take an antiviral drug as a preventive measure. 

That type of specific treatment or preventative measure is not yet available for COVID-19, though there are several drugs currently undergoing trials.

If you get sick, you get tested, and you're waiting for the results, keep your distance yourself from others, rest up, and stay hydrated. While you're recovering, stay in contact with your provider—if your symptoms become severe, you might need to go into the hospital for treatment.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.