Jul 08, 2020 3:00 PM

Author: Kylene Metzger


When coronavirus, or COVID-19, first impacted the United States earlier this year, similarities in symptoms of influenza and coronavirus made it difficult to tell the difference between the viruses. Both are contagious respiratory illnesses, but there are some key differences between the two.

Similarities in Symptoms

  • Fever
  • Cough
  • Shortness of breath/difficulty breathing
  • Fatigue
  • Sore throat
  • Runny or stuffy nose
  • Muscle pain or body aces
  • Headache
  • Vomiting and diarrhea, though this is more common in children than adults

For both COVID-19 and flu, one or more days can pass between a person becoming infected and when they start to experience illness symptoms.

Differences in Symptoms

  • Loss of taste and smell

According to the CDC, a person with COVID-19 could take longer to develop symptoms than if they had flu. A person typically develops symptoms five days after being infected, but symptoms can appear as early as two days after infection or as late as 14 days after infection, and the time range can vary. A person who develops flu symptoms can range anywhere from one to four days after infection.  

“The flu usually doesn’t last that long. The length of illness for COVID-19 patients seems to differ.”

Emily Spivak, MD, MHS, FIDSA, Division of Infectious Diseases

Similarities in Transmission

  • It’s possible to spread COVID-19 and flu for at least one day before experiencing symptoms.
  • Both viruses can spread from person-to-person between people who are in close contact with each other.
  • Both are spread mainly by droplets such as when a person coughs, sneezes, or talks.
  • A person could possibly get infected by physical human contact or by touching a surface that has the virus on it.

Differences in Transmission

A person with COVID-19 may be contagious for a longer period of time. How long someone can spread the virus is under investigation by the CDC. It’s possible for people to spread the virus for about two days before experiencing symptoms and remain contagious for at least ten days after signs of symptoms first appeared.

According to the CDC, COVID-19 is more contagious among certain populations and age groups than flu. The virus that causes COVID-19 can quickly and more easily spread to a lot of people and result in continuous spreading among people as time progresses.

Similarities Among High-Risk Groups

  • Older adults
  • People with certain underlying medical conditions
  • Pregnant people

Differences Among High-Risk Groups

“We aren’t seeing many children infected with COVID-19. There are after-affects such as MIS-C, but children not being affected with respiratory illness is unique with the virus that causes COVID-19.”

Emily Spivak, MD, MHS, FIDSA, Division of Infectious Diseases

Unique Characteristics of COVID-19

  •  Asymptomatic transmission
    • People who do not exhibit any symptoms of COVID-19 may be infected with the virus and spread it to others. These people could have mild, cold-like symptoms or have no symptoms at all.

“COVID-19 is unique and different from other respiratory viruses in that people tend to have some of the highest viral amounts in the several days before they are symptomatic before they know they have the disease. This is why there is an emphasis on universal use of face masks to help control virus spread before a person knows they have it.”

Emily Spivak, MD, MHS, FIDSA, Division of Infectious Diseases
  • Weather
    • Transmission has not slowed down in warmer weather as seen with the flu every year.
  •  Vaccine
    • There is currently no vaccine to prevent COVID-19. There are currently multiple FDA-licensed influenza vaccines to protect against the three or four viruses that scientists anticipate will circulate each year.

“Knowing that we have a vaccine for influenza is probably reassuring to people and makes it less scary. The fact that we have no vaccine or preventative measures makes COVID-19 scary.”

Emily Spivak, MD, MHS, FIDSA, Division of Infectious Diseases

Kylene Metzger

Public Affairs

coronavirus covid-19 influenza flu wellness

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