Coronavirus vs. Flu Symptoms: How to Tell the Difference

While COVID and the flu are different viruses, they certainly seem to act similarly. Dr. Stephen Rinderknecht, chair of the immunization committee for UnityPoint Health, breaks down flu vs COVID symptoms along with similarities and differences between the two viruses as we head into flu season.

Flu vs. Coronavirus: Similarities

They're Both Viruses 

When considering the flu vs COVID, it’s first best to understand they’re both viruses, not bacteria. Bacteria are very small organisms composed of a single cell, while a virus is even smaller. Infections from viruses are more common, especially during the fall and winter. Viruses can’t be treated by antibiotics. Those only help treat bacterial infections. People who have conditions that put them at high risk for severe influenza or COVID-19 may be eligible for antiviral medications.

They Both Spread in Three Ways

• Inhalation: Breathing in very small, fine particles containing the virus. An example of this is breathing in particles that linger in the air after an infected person was talking loudly or singing.
• Deposition: The virus is carried by exhaled droplets that land directly onto exposed mucous membranes — like the nose or mouth. An example of this is when someone sneezes or coughs on you.
• Touching: When you touch your own nose or mouth (mucous membranes) with fingers after directly touching germs (like a dirty tissue) or other germ-filled surfaces (door handles, shared toys etc.).
  

Preventing the Spread of COVID-19 and the Flu

“Fortunately, the best measures we have for decreasing the spread of COVID-19 also work on influenza, since they’re both spread the same way. Make sure you do your part by following CDC guidelines, continuing frequent hand washing and staying home when you’re sick,” Dr. Rinderknecht says.

COVID-19 and Flu Vaccines

You can help prevent serious illness, hospitalization and death of both viruses by getting vaccinated. You can get both the flu vaccine and the COVID-19 vaccine in the same doctor’s visit. Even if you’ve had COVID-19 or the flu in the past, it’s still a good idea to get vaccinated against the viruses.

Learn More about Scheduling a Vaccine

Coronavirus vs Flu Symptoms Difference

While the lists of symptoms of COVID vs flu are similar, there are a couple on the COVID symptom list that aren’t on the flu list. Those include shortness of breath, difficulty breathing and new loss of taste or smell. If you have any of the symptoms on either of these lists, talk with your provider to help determine if testing is needed.

Flu Onset is Faster

It’s important to pay attention to when and how you feel symptoms in your body.

“Typically, influenza starts very abruptly with fever and cough. People can often tell me not just the day, but the hour they became ill. The symptoms of COVID seem to come on more gradually, and the non-respiratory symptoms (fatigue, aches, vomiting, diarrhea, loss of smell/taste etc.) can be the first to show up,” Dr. Rinderknecht says.

What are New Symptoms of COVID 2025?

COVID symptoms largely remain consistent, still presenting as loss of taste/smell, congestion, headaches, fatigue, body aches, cough, sore throat and fever. However, some patients have anecdotally reported a new and intense symptom: a "razor blade throat," characterized by a sharp, scraping sensation when swallowing. This particularly severe sore throat is linked to NB.1.8.1, or "Nimbus," a subvariant of Omicron that’s been the dominant COVID variant since late 2021. Generally, Omicron variants are known to cause more prominent throat problems compared to earlier forms of the virus. 

Doctor’s Advice

Simple — get vaccinated.

“We know that a person can be infected by more than one respiratory virus at the same time (co-infection). When co-infection has occurred with other respiratory viruses, it often results in a more severe and potentially deadly disease,” Dr. Rinderknecht says.