COVID-19 or Influenza – How to Tell


  • COVID-19 infections are widespread in most communities.
  • During the winter, influenza (flu) infections also become widespread.
  • Here is some advice on what to do when both viruses are in town.

COVID-19 and Flu – How They are Similar

  • Presenting Symptoms. They are nearly the same. You will not be able to tell them apart when you are sick.
    • Fever and cough are the most common symptoms for both.
    • Other respiratory symptoms such as sore throat and runny nose are common for both.
    • Muscle aches and feeling very tired are seen with both.
    • The only helpful symptom is loss of taste or smell. It points to COVID-19, but it only occurs in 15% of COVID-19 patients.
  • Viral Tests. Tests are available for both viruses. Both are done with nose or throat swabs. Testing is the only way to tell the right diagnosis. It’s the only way to know for sure what someone has.
  • Types of Complications. These are nearly the same. The most common serious symptom is trouble breathing (shortness of breath). It usually means the patient has developed pneumonia. Other complications in young children are croup or wheezing (tight breathing). They are due to a child’s smaller airway and can occur with either virus.
  • High-Risk Factors for Complications. The most common high-risk factors are older age (elderly), weak immune system (from illness or medicines), lung disease, heart disease, diabetes and obesity. The CDC’s high-risk patient list for the flu is similar to the list for patients with COVID-19.
  • How it Spreads. Both are spread person-to-person by respiratory droplets. Droplets are produced by coughing, sneezing, shouting or singing. They get inhaled by a nearby person or quickly fall to the floor or ground.
  • Infections without Symptoms. Both infections can occur without causing any symptoms (asymptomatic people). These people can spread the disease to others. But, spread by people with no symptoms happens at a much lower rate than for people with symptoms.
  • Home Treatment. It’s the same for both viruses. Treat the symptoms that bother you the most. Provide symptom relief as needed for the cough, sore throat and fever. Drink extra fluids and stay well-hydrated. When tired, get extra rest. See the COVID-19 Diagnosed or Suspected topic for details.
  • Prevention. Getting the vaccines and booster shots can help prevent both diseases. Wearing face masks and social distancing have been proven to help prevent both diseases.

COVID-19 and Flu – How They Differ

  • Anti-viral Medicines.
    • Flu: prescription anti-virals given by mouth (such as Tamiflu) are available for the flu. They are mainly prescribed for sick patients who also are high-risk for complications. Healthy people don’t need anti-viral medication if they get flu.
    • COVID-19: prescription anti-viral medicines are available for high-risk patients older than 12 years who get COVID-19.
  • Home Isolation for Sick People with Symptoms. Home isolation for COVID-19 is recommended for 5 full days after the day symptoms started. Home isolation for flu is recommended until the fever has been gone for at least 24 hours.
  • How Soon Symptoms Occur after Exposure. The incubation period is how many days after close contact with a sick person the symptoms start. Flu and COVID-19 symptoms start on the average 2 or 3 days after exposure to a sick person.
  • Time of Year. The flu is seasonal, usually October to April. It peaks December through February. COVID-19 is not seasonal. It will not go away in the spring like flu.
  • Severity and Death Rate. COVID-19 is more dangerous than flu. COVID-19 has a higher complication rate. COVID-19 vaccines greatly reduce that difference.

Care Advice


Getting both infections at the same time could cause more severe complications.

Getting them close together is also risky. The first one could weaken your body for when the second one starts.

Become an expert on prevention. Trust the science.

Here is some advice to help you get through this flu season.

Influenza Vaccine – Be Smart and Get Your Flu Shot:

  • Getting your annual flu shot is the best way to protect your family from flu.
  • Reason: getting COVID-19 while you also have the flu, or are recovering from it, may increase the chances of getting severe complications.
  • Flu vaccines are strongly advised for all children greater than 6 months of age (AAP).
  • All adults and children should get a flu shot, not just those at higher risk for complications.
  • Most often, the flu shot prevents getting any flu infection. If the vaccine does not cover a new flu virus and you get it, the shot still helps to reduce your symptoms.
  • Getting the flu shot will turn on and rev up your immune system. Research shows that it might even reduce your chances of getting COVID-19.

COVID-19 Vaccine – Get Your COVID-19 Shot and a Booster:

  • Vaccines have saved more lives than any other public health action. They are the most powerful weapon we have against deadly infectious diseases. Follow the science.
  • Safe and effective vaccines are available for people age 6 months and older. COVID-19 vaccines prevent serious complications, hospitalizations and death.
  • Get your COVID-19 vaccine and booster when eligible. It could save your life and protect your family.
  • Vaccine Sites: find a nearby vaccine site at or call your doctor’s office.

Protect Your Family from Catching COVID-19 and Flu:

  • Face masks. Wear a face mask when you leave your home when community spread is high. Face masks reduce the spread of both infections. Even after you get the vaccine and a booster, face masks offer additional protection.

  • Wash your hands often with soap and water. Always wash before eating.

  • Use an alcohol-based hand sanitizer, if water is not available. Note: soap and water work even better.

  • Don’t touch your eyes, nose or mouth unless your hands are clean. Germs on your hands can get into your body this way.

  • Try to avoid contact with sick people.

  • Social (Safe) Distancing. During the times of outbreaks, try to stay at least 6 feet (2 meters) away from anyone who is sick. Avoid crowds because you can’t tell who might be sick.


Author: Barton Schmitt, MD, FAAP Copyright 2023. Updated May 10, 2023.
Disclaimer: this health information is for educational purposes only. You, the reader, assume full responsibility for how you choose to use it.