Stomach Flu vs. COVID-19: Here's How To Tell the Difference

Doctors explain how to differentiate between the two by noting your symptoms.

One of the biggest problems doctors face in diagnosing and treating COVID-19 patients is that SARS-CoV-2 causes many symptoms that are also signs of other diseases (aka nonspecific symptoms).

That means that while people who fall ill with COVID-19 could show symptoms like fever, dry cough, and headache, those symptoms can also be related to allergies, the flu, or even the common cold.

But the symptom similarities don't stop there—COVID-19 has been linked to gastrointestinal issues (nausea, vomiting, and diarrhea), which are also symptoms of the stomach flu, technically called gastroenteritis. But how do you know if you're suffering from one or the other? Health spoke to experts to find out how to spot the differences—and how to proceed before going into your primary care doctor's office for treatment.

What Are the Symptoms of Stomach Flu vs. COVID-19 Symptoms?

For starters, it's important to understand that gastroenteritis isn't actually a type of flu, even if it's colloquially known as stomach flu. According to MedlinePlus, a resource from the US National Library of Medicine, gastroenteritis occurs when the lining of your intestines becomes inflamed. This can be the result of viruses, parasites, or bacteria, per MedlinePlus.

Chances are you've either had it yourself or you, at least, know someone who has: Viral gastroenteritis is the second most common illness in the country, according to MedlinePlus. It's spread through contaminated food or water and contact with an infected individual. Below are the symptoms of gastroenteritis:

  • Diarrhea
  • Vomiting
  • Abdominal pain
  • Fever
  • Headache
  • Chills

Fortunately, most people recover from gastroenteritis without any treatment. That said, dehydration is a common side effect because oftentimes, gastroenteritis causes patients to lose a lot of fluid through diarrhea and vomiting. In order to keep from becoming dehydrated, you might have to drink more fluids than you usually do while you're fighting off the illness.

COVID-19, on the other hand, is an infectious disease caused by a coronavirus that was newly discovered in 2019, known as SARS-CoV-2. For the most part, according to the World Health Organization (WHO), those who get COVID-19 will experience a mild to moderate respiratory illness and will often recover without medical treatment. But others—people over the age of 65 or those with other underlying conditions—are more likely to develop severe illness from the virus.

One of the ways SARS-CoV-2 spreads is through infected respiratory droplets (like those that come from sneezes, coughs, or speaking), which is why mask-wearing is beneficial. And if the symptoms of the stomach flu look familiar, it could be because many of them are also signs of COVID-19. The most common symptoms are:

  • Cough
  • Chills or fever
  • Difficulty breathing or shortness of breath
  • Body or muscle aches
  • Fatigue
  • Loss of smell or taste
  • Headache
  • Runny nose or congestion
  • Sore throat
  • Vomiting
  • Nausea
  • Diarrhea

How Do You Tell the Difference Between COVID-19 and the Stomach Flu?

So, how do you know which one you're dealing with if you're experiencing, for instance, a fever, vomiting, and diarrhea? Unfortunately, the answer isn't clear cut, Cory Fisher, DO, who specializes in family medicine at Cleveland Clinic, told Health. Among things to watch for are upper respiratory symptoms and loss of taste and smell since those differentiate gastroenteritis from COVID-19, said Dr. Fisher. "There are a lot of overlapping symptoms, although COVID-19 tends to have more upper respiratory symptoms, cough, and a hallmark characteristic of loss of taste or smell," explained Dr. Fisher.

Another hint that you're dealing with COVID-19 rather than the stomach flu is chest pains, Tania Elliott, MD, who specializes in infectious diseases at NYU Langone, told Health. "There are some symptoms more specific to COVID-19, like loss of taste and smell, cough, or chest pains," explained Dr. Elliott, adding, "Patients do not generally get these symptoms with a stomach flu."

If you're worried you have COVID-19, you should also keep in mind the infection rate in your town or community. If the infection rate is high or you've come into contact with someone with COVID-19, you might not want to write off your symptoms as gastroenteritis right away. "If a patient has had any known exposure to COVID-19, these symptoms are much more concerning. In the end, it can be very difficult to tell clinically what the infectious agent is, and the one best way to know the difference is to get a coronavirus test," said Dr. Elliott.

Regardless, the first step in addressing either your stomach flu or COVID-19 symptoms is probably putting in a call to your primary care doctor, said Dr. Fisher. (Unless, of course, you're experiencing life-threatening symptoms such as difficulty breathing, in which case you should head to your local emergency room.) "I recommend calling your doctor and scheduling a telehealth visit so they can direct you to next steps, [including] how and where to get tested," said Dr. Fisher. Overall, a telehealth visit can protect you from COVID-19 if you don't have it and protect others from whatever's ailing you. "The emergency department and other high-level care locations should be reserved for those with severe symptoms, like shortness of breath or chest pain," said Dr. Elliot.

From there, your doctor can make their best guess on which virus may be causing your symptoms and offer advice on how to start feeling better. If you're seriously ill, seek medical attention. If you're well enough to stay home and care for yourself there, your best bet for either illness will be symptom management. If you're experiencing diarrhea or vomiting, the best route there is, again, to remain as hydrated as possible.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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