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Flu vs. Coronavirus: What’s the Difference?

8 frequently asked questions about flu, COVID-19 and vaccines

A young African-American man gets vaccinated by health care provider wearing a mask.

8 frequently asked questions about flu, COVID-19 and vaccines

The flu season is here. And once again, it’s happening during the COVID-19 pandemic. The biggest difference is that this time vaccines for both are widely available.


Health care providers strongly encourage people to be fully vaccinated against both diseases to prevent illness. They worry that a surge in flu and COVID-related illnesses could severely challenge hospitals and other health care resources.


“Last year’s flu season was relatively mild because everyone was taking precautions for COVID, which also helped prevent the spread of flu,” says Ghazala Sharieff, MD, MBA, Scripps Health chief medical officer, clinical excellence and experience. “But there is concern that we may not get so lucky this time because the precautions aren’t being as carefully followed since the requirements have been relaxed.”


COVID-19 vaccines, which were just being rolled out during the last flu season, are now readily available to anyone who needs them. Unvaccinated people currently account for the vast majority of people who’ve been hospitalized or died from COVID.


This year’s seasonal flu vaccine is also widely accessible and offers protection against the most common strains of the flu virus.


The following are frequently asked questions about the flu, COVID-19 and vaccine protection.

1. Is COVID-19 different from the seasonal flu?

Flu and COVID-19 are both contagious respiratory illnesses but are caused by different viruses.


COVID-19 is caused by infection with a novel coronavirus known as SARS-CoV-2. Flu is caused by infection with influenza viruses. Both can spread from person to person, especially when in close contact. People can be infected by both at the same time.


“Because some of the symptoms of COVID-19 and flu are similar, it may be hard to tell the difference based on symptoms alone, and testing may be needed to help determine the cause of those symptoms,” Dr. Sharieff says.

2. What are similarities and differences between flu and COVID-19 symptoms?

Similarities in symptoms between flu and COVID-19 include:


  • Fever or chills
  • Cough
  • Shortness of breath
  • Fatigue
  • Sore throat
  • Runny or stuffy nose
  • Muscle pain or body aches
  • Headache
  • Vomiting and diarrhea in some cases
  • Change in or loss of taste or smell, though this is more common with COVID-19.


People tend to develop flu symptoms one to four days after infection. COVID-19 symptoms may appear two to 14 days after infection.

3. Does the flu vaccine protect against COVID-19?

The flu vaccines do not protect against COVID-19. This means that people who’ve been vaccinated for COVID-19 but not the flu can get sick from the flu.

4. Who needs a flu shot?

The flu vaccine is recommended for everyone 6 months or older, especially people who are at high risk from complications from the flu, including:


  • People 65 and older
  • Children under the age of 2
  • Pregnant women
  • People with chronic conditions, such as asthma, diabetes, heart disease, neurological conditions, blood disorders, weakened immune systems and morbid obesity. 


Flu seasons are hard to predict but there could be an increase in flu activity this fall and winter due to relaxation of COVID-19 mitigation measures, such as stay-at-home orders or mask mandates.

5. Can I get flu and COVID shot during the same visit?

“It is safe to receive both vaccines at the same time,” says Dr. Sharieff. “Being vaccinated for both viruses is the best thing you can do to protect yourself from these potentially dangerous illnesses.”


To see if you are eligible for a booster shot for the COVID-19 vaccine, check with the Centers for Disease Control and Prevention (CDC).

6. Is COVID-19 more dangerous than flu?

Flu and COVID-19 can both result in serious illness that can lead to hospitalization and even death. COVID-19 appears to be more contagious. Severe illness and death are more frequent with COVID than with flu.

7. When should I get a flu vaccine?

The CDC recommends getting a flu shot between now and the end of October. But it can be done as late as January or as long as flu viruses are circulating.

8. Where is the safest place to get a flu vaccine?

A flu vaccine can be safely received at multiple locations, including your doctor’s office, clinics, health departments and pharmacies.


Scripps patients can use the MyScripps portal to receive vaccination for influenza, COVID-19, pneumonia and other illnesses, or they can call their primary care physician’s office directly.