Dr. Dan Fulton explains the difference between COVID-19 and the seasonal flu.

As flu season quickly approaches, it may be difficult to tell whether your symptoms are from the flu, a common cold or COVID-19.

Coronavirus and the flu may have similar symptoms but have vastly different long-term implications and death tolls. 

The Centers for Disease Control and Prevention (CDC) estimated in the United States’ 2019 to 2020 flu season, between 39 million and 56 million people got sick with the flu and 24,000 to 62,000 died as a result. By these estimates, the mortality rate for last year’s flu season would be around 0.1 percent.

Since the first case of COVID-19 was reported in the United States on Jan. 21, 8,249,011 people have been infected and 220,362 individuals have died from COVID-19, though the number could be higher based on the CDC’s finding of evidence which points to earlier community spread. 

By these numbers, the mortality rate of coronavirus would be around 2.7 percent. 

There are many common symptoms between the two, including a cough, fever and sometimes, bodily aches and pains.

symptom chart

This chart outlines the symptom differences between COVID-19, the flu, the common cold and allergies.

Dr. Dan Fulton, infectious disease specialist at Mary Greeley Medical Center, explained the difference between COVID-19 and the seasonal flu and how to tell which one you may be experiencing symptoms of. 

“Both influenza and COVID-19 are respiratory illnesses that achieve their infection through entrance of the upper airway — nose or mouth — and then cause localized infection of the upper airway," Fulton said. "Then, sometimes [they] progress into the lower airway and can cause a viral pneumonia. … In that sense, they both act in a very similar way. They both have different receptors for how they gain entrance into the respiratory system, but ultimately, they both function in the same way as they enter the respiratory system, take over the cellular machinery, then replicate themselves and eventually spread to other surrounding tissue.”

Fulton also added both viruses cause a significant immune response that travels through the same viral pathway of immunity, making symptoms between the two extremely similar.

“The hallmark of these viruses are that they cause fever and then generalized symptoms of body aches, headaches, fatigue,” Fulton said. “And if they do start to cause more of a pneumonia-like syndrome, people develop cough and shortness of breath.” 

Fulton said the biggest symptom difference he is aware of is the loss of taste and smell that is caused by COVID-19. 

“That [loss of taste and smell] seems much more common with COVID-19 than it is with influenza, although influenza could potentially cause that as well,” Fulton said.

Something Fulton mentioned is it seems like COVID-19 is probably much more contagious than influenza.

“So when we talk about the number of viral particles somebody needs to be exposed to, that number is probably less with COVID-19, which is part of the reason why it has spread so quickly,” Fulton said.

He also mentioned there is a vaccine for influenza but not yet one for coronavirus and encouraged everyone to get vaccinated against the flu.

“You will often hear it said that the influenza vaccine has incomplete effectiveness, sometimes quoted as 40 to 50 percent,” Fulton said. “But I think it’s important that people remember that if somebody has gotten the influenza vaccine and gets influenza, it is very likely that their influenza illness will be much less severe than if they hadn’t gotten the vaccine.”

Fulton said he thinks this season may create difficulty for physicians to determine the difference between COVID-19 and the flu based solely on symptoms. 

“There will definitely be testing available to go both ways to figure it out,” Fulton said. “The challenge with that is if COVID-19 is a potential diagnosis, then providers will need to take appropriate caution with regards to the protective gear and all of that.” 

Because coronavirus is likely more contagious than the flu as Fulton mentioned, doctors, nurses and care providers wear more personal protective equipment than they would when just testing for influenza. 

“Those of us in health care kind of see this dual-infection wave coming that will be a stress on the health care system,” Fulton said.

Fulton stressed the importance of health precautions, such as mask-wearing, hand-washing, avoiding large indoor gatherings and continued physical distancing going into the fall and winter.

“Students will need to work to maintain smaller gatherings to avoid rapid spread,” Fulton said. 

He said he also thinks people that have already had COVID-19 and recovered fully are immune to getting it again.

“There are rare reports of people having it again, getting it a second time, but that is not the general rule,” Fulton said. “That is the exception.”

Fulton also brought up recent CDC concerns about the spread of COVID-19 in households during the holiday season. 

“That would, I think for students, be particularly important to consider as the holidays come up,” Fulton said. “If they are going home to visit elderly grandparents or people that would be at much higher risk than the student would be for a severe course of COVID-19, they should just be thoughtful about taking precautions, even with family. … I do think the holidays will need to look different this year than they did in prior years while we try to get through this pandemic together.” 

Fulton said he’s hopeful there will be a vaccine for COVID-19 that is safe and effective, and by spring 2021, there will hopefully be signs about availability of the vaccine.

“That’s sort of the best-case scenario, but I think there’s reason to be hopeful about that,” Fulton said.

Iowa State is continuing to do COVID-19 testing, and numbers on campus have been low over the last few weeks. Updated information regarding the coronavirus pandemic on campus can be found on Iowa State’s COVID-19 dashboard. 

(1) comment

Noah Kopischke

This report is respectable, but I do have one concern. You say that the influenza virus infected 39 to 56 million people, compared to coronavirus infecting 8 million people, yet also say that coronavirus spreads much faster. This seems logically inconsistent. My assumption is that coronavirus does spread faster, and the reason for this inconsistency is that for influenza you reported the Infection Fatality Rate (IFR) and for coronavirus you reported the Case Fatality Rate (CFR). In order to compare these two viruses accurately, make sure you compare the CFRs of each or the IFRs of each. The estimates I've heard are that the infections for coronavirus are about ten times the number of cases, so multiply 8 million by 10 to get 80 million and you would be able to compare the two more accurately. This comparison would show that coronavirus is still 2.7 times more deadly than influenza with a .27 IFR.

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