Distinguishing Between COVID-19 and Flu

February 24, 2021
Distinguishing Between COVID-19 and Flu


COVID-19 and seasonal influenza are caused by different viruses, which can make it challenging to differentiate between the two respiratory illnesses. 

While flu activity is unusually low this year due to pandemic safety precautions, COVID-19 continues to still affect many people across the country. 

To learn more about the viruses, BayCare provides some information on symptoms, treatments, vaccines and how to distinguish between influenza and COVID. 

Difference between COVID-19 and Flu 

Flu and COVID-19 are contagious respiratory infections and are triggered by different viruses. COVID-19 is caused by infection with a new coronavirus (called SARS-CoV-2), and flu is caused by infection with influenza viruses.

COVID-19 appears to spread easier than flu and tends to cause more serious illnesses. It could also take longer before people show symptoms and it can be more contagious for a longer period of time. 

Flu, also known as influenza, is a respiratory infection that most often affects the nose, throat, and lungs. Flu can be very contagious and can vary from minor to severe. This infection hits its peak in the fall-winter months and can spread quickly in various environments affecting children and adults of all ages.


COVID-19 common symptoms include fever, cough, shortness of breath, sore throat, headache, loss of taste and smell, congestion, nausea or vomiting and diarrhea.
Flu symptoms include fever, chills, cough, sore throat, runny or stuffy nose, muscle and body aches, headaches, fatigue, vomiting and diarrhea. 

According to the Centers for Disease Control and Prevention (CDC), flu viruses can cause mild to severe illness, especially in persons with underlying health conditions and in the elderly. With COVID-19, some patients can have loss of taste or smell, which is not a symptom of flu. 

Is it COVID-19 or Flu?

Both viruses cause similar symptoms. This makes it more difficult to determine if someone has COVID-19 or flu. However, diagnostic testing helps determine if you are sick with flu or COVID-19. BayCare offers flu testing at BayCare Urgent Care centers and primary care offices across the system. BayCare also offers testing options for COVID-19.

How the Viruses Spread

Both COVID-19 and flu can spread from person to person, and between people who are in close contact with one another (within about 6 feet). Both viruses are spread mainly by droplets when those carrying the illnesses cough, sneeze, or talk. The droplets typically land in the mouths or noses of people who are in close proximity that could potentially get inhaled into the lungs.

If someone develops the flu, symptoms show quickly and can be contagious for one day before symptoms appear. If a person has COVID-19, it could take them one to fourteen days (average is 4-5 days) after infection to develop symptoms and can be infectious for as long as 10-20 days after symptoms start. 

People at High Risk for Severe Illness 

COVID and flu can cause severe illness and complications. Those at high risk for complications include older adults, pregnant women and those with underlying medical conditions. Healthy children have a higher risk for flu complications compared to COVID-19. However, infants and children with underlying medical conditions are at increased risk for both flu and COVID-19 severe disease and complications.

Treatment Options

There are several treatments available for COVID-19 and flu. People who have been diagnosed with flu can be treated with antiviral drugs approved by the U.S. Food and Drug Administration. While COVID-19 is a relatively new virus, the FDA has approved for emergency use several promising treatments for the virus including remdesivir, dexamethasone and monoclonal antibody treatments. 


It’s important to receive the flu vaccine every year. This vaccine can help reduce the severity of flu illnesses, hospitalizations and even deaths. 

Like the flu vaccine, the COVID vaccine helps prevent people from getting infected, and help reduce the likelihood of severe disease and death. While scientists around the world have raced against time to develop a COVID-19 vaccine, the FDA’s rigorous review classifies them as safe and effective. The vaccines have shown promising results and no major side effects to date. 

Get Care Now

If you think you’re experiencing flu or cold symptoms, BayCare provides convenient access to different care options and services for patients and their families. BayCare’s telehealth services and multiple convenient locations provide access to the right care at the right place for the right price to our patients and the community. 

Patients can conveniently see a doctor using BayCareAnywhere, a 24/7 mobile application offering virtual visits through a smartphone, tablet or computer. They can also see a doctor at 36 Walk-In Care locations at select Publix Pharmacies throughout the Tampa Bay area. BayCare’s 19 urgent care locations throughout Pinellas, Hillsborough, Polk and Pasco counties, also offer quick, high quality health care for adults and children ages two and older. For more information, visit BayCareGetCareNow.org.

If you think you have been exposed to COVID-19, use our checklist to determine if you meet the definition of exposure. If you have symptoms of COVID-19, contact a primary care physician, see a health care provider on BayCareAnywhere or visit one of BayCare Urgent Care clinics. BayCare also offers the Online Screening Tool. If you think you should get tested, learn more about BayCare’s various testing options here. For more information on COVID-19, visit BayCare.org/Coronavirus


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