Are Influenza (Flu) & COVID-19 Caused by the Same Virus?

Kenneth Knowles, MD
Medically reviewed by Kenneth Knowles, MDFebruary 7th, 2022
Woman looking at the thermometer on the couch

The short answer? No. While influenza (flu) and COVID-19 share a number of symptoms, they are not caused by the same virus. Both contagious respiratory infections have multiple variants that can be easily spread from person to person. In this article, we’ll be taking a closer look at the differences and similarities between flu and COVID-19, their variants, and how to best determine which infection you have.

Coronavirus SARS-CoV-2: The Virus Behind COVID-19

There are many types of coronaviruses. However, the novel coronavirus identified in December 2019—SARS-CoV-2—is the virus behind COVID-19. This virus is very contagious, spreading from person to person via droplets and particles released into the air when an infected person breathes, speaks, laughs, sneezes, etc. The droplets can linger on surfaces and accumulate in enclosed areas with a lot of people. When compared to the flu, COVID-19 can lead to more serious complications in high-risk individuals. It can also take a longer amount of time for infected people to show the first signs of COVID-19 symptoms, as they typically appear anywhere from two to 14 days after exposure. The only way to accurately diagnose COVID-19 is through laboratory testing, as its symptoms are similar to other respiratory illnesses and viruses.

Over time, the coronavirus SARS-CoV-2 has mutated, resulting in new variants of COVID-19: Delta and Omicron. These new variants were expected, as viruses constantly change as they fight to survive. Both Omicron and Delta have proven to spread more easily than the initial variant. Delta, however, has been shown to cause more severe complications than the other variants. You can learn more about these COVID-19 variants here.

Influenza A & B: The Viruses Behind the Flu

There are four types of influenza viruses, but only two are behind the infamous seasonal epidemic better known as flu season: human influenza A and B viruses. Influenza A viruses are divided into subtypes, while influenza B viruses are classified into lineages. Both types of influenza viruses are contagious and mainly spread via droplets from an infected individual. People with the flu are most contagious in the first four days of contraction, with symptoms beginning around two days after the virus enters the body. The only way to confirm a flu diagnosis is with laboratory testing, as its symptoms are similar to other respiratory illnesses and viruses.

Seasonal flu vaccines are formulated to protect against both types of influenza viruses as well as flu viruses that are antigenically similar to the strains used to make the vaccine. Just like coronaviruses, influenza A and B types have been shown to mutate over time.

Can You Spot the Similarities & Differences?

If COVID-19, influenza, common respiratory colds, and allergies all share common symptoms, then how can you tell which condition is affecting your health? While common colds and allergies are low-risk infections with symptoms that can typically be treated at home with rest and over-the-counter medications, COVID-19 and the flu are caused by contagious viruses that can spread rapidly and exacerbate quickly in high-risk individuals. Those who become seriously ill from the flu or COVID-19 should receive professional medical care and testing to confirm a diagnosis, as the ability to pinpoint which virus you have cannot be determined by symptoms alone. Shared symptoms that can confuse a COVID-19 or flu self-diagnosis include:

In short, viral infections—be it COVID-19, influenza, or another upper respiratory infection—present a whole host of symptoms that can make determining a diagnosis impossible for the average person. Receiving a confirmed diagnosis through laboratory testing is the best way to find out what you have and establish a treatment plan.

DispatchHealth Provides In-Home Medical Care

Whether it’s COVID-19 or influenza, DispatchHealth offers practical in-home treatment for non-life-threatening viral infections. We make the process of receiving medical support for acute and advanced health conditions easy by delivering our services to your home! Upon request, our certified team will arrive at your doorstep with a medical kit that contains roughly all of the tools and technologies you’d find at a traditional ER. DispatchHealth’s traveling flu crew (available only in select locations) is also ready to help diagnose and treat patients with flu symptoms from the comfort of their homes.

You can learn more about DispatchHealth’s in-home medical service by exploring our site or requesting care today. We’re rapidly growing and covering new markets across the country!


DispatchHealth relies only on authoritative sources, including medical associations, research institutions, and peer-reviewed medical studies.

Sources referenced in this article:


    About DispatchHealth

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    DispatchHealth works in conjunction with health systems, provider groups, senior living communities, home health organizations, payers and employers to provide a comprehensive spectrum of healthcare services, ensuring that most patients with acute, intensive, or chronic health conditions can receive exceptional and cost-effective medical care at home. We provide top-rated, high-acuity healthcare for medically complex patients in their home.

    Patients can also contact DispatchHealth directly by phone, app or website. DispatchHealth is partnered with most major insurance companies.

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