COVID-19 vs. the Flu: How Can You Tell the Difference?

Sick woman wrapped in blanket holding a mug

There are a lot of questions surrounding COVID-19, and as we enter flu season, many people are wondering how similar the coronavirus is to the flu and how to tell the difference.

Let’s break down the similarities and differences in symptoms, communicability, complications and treatments of the viruses.

The Difference Between Coronavirus and the Flu 

Both COVID-19 and the flu are contagious respiratory illnesses, but each is caused by a different virus. Coronavirus is caused by SARS-CoV-2, while the flu can be caused by different influenza viruses.

Both spread through droplets expelled when a person coughs, sneezes or talks. While both viruses have been associated with super-spreader events (times when infected individuals infect a disproportionately higher number of people than usual) reports of such events due to COVID-19 far outpace those due to influenza.

Coronavirus Symptoms vs. Flu Symptoms

Symptoms of both coronavirus and the flu include: 

  • Fever or chills
  • Cough
  • Shortness of breath
  • Fatigue 
  • Headache
  • Muscle pains or aches
  • Sore throat 

COVID-19 symptoms can also include loss of smell or taste and can take longer to develop than flu symptoms. In positive coronavirus cases, symptoms typically appear five days after infection, but can develop as early as two days or as late as 14 days.

Flu symptoms usually take between one and four days to appear and last only a week or two, while COVID symptoms can linger for an average of seven to 21 days.

Those sick with the flu are the most contagious during the initial three to four days after infection, and could be contagious for about one day before the onset of signs of illness. Those who have tested positive for coronavirus can spread the virus for about two days before experiencing symptoms, and can remain contagious for roughly 10 days once symptoms appear. If patients are asymptomatic or if symptoms subside, it is still possible for them to remain contagious for at least 10 days after testing positive.

Complications and Risk

In terms of high-risk cases, both COVID-19 and the flu can result in severe illness and complications for older adults, those with underlying medical conditions and those who are pregnant. Both can cause complications like pneumonia, respiratory failure, sepsis, cardiac injury or organ failure. Known complications  unique to COVID-19 include blood clots in veins or arteries of the lungs, heart, legs or brain which can lead to heart attack or stroke.

While healthy children are at greater risk for the flu than coronavirus, infants and children with underlying conditions are at increased risk for both. Although rare, one COVID-19 complication seen in children is Multisystem Inflammatory Syndrome in Children (MIS-C). This can cause inflammation of different body parts including the heart, lungs, kidneys, brain, skin, eyes or GI organs. Learn more about symptoms and what to do if you think your child is sick with MIS-C. 

Treatments and Vaccines for COVID-19 and the Flu

To avoid illness and promote immunity, there are multiple FDA-licensed flu vaccines produced annually to fight against three or four different strains that scientists anticipate will circulate each season. If infected with an influenza virus, there are FDA-approved prescription antiviral drugs available to help lessen the severity of symptoms and shorten infection periods.

Currently, for COVID-19 there are two vaccines receiving emergency use authorization by the FDA. Research on a multitude of other vaccine candidates continues to be conducted, and many clinical trials are well underway.

In October 2020, the FDA approved the antiviral drug remdesivir to treat COVID-19. Early clinical trials suggest remdesivir may reduce time to recovery. While not specifically approved for COVID-19, the steroid drug dexamethasone has been shown to reduce deaths in hospitalized patients with respiratory failure due to COVID-19. In addition, a variety of experimental strategies including pooled plasma from recovered patients and several laboratory-created antibodies have received FDA expanded use permission and are being studied for COVID-19.

Is Coronavirus Worse than the Flu? 

Scientists are still learning a lot about COVID-19. They’re working to understand how and why some people react differently to the disease than others, why up to 40 percent of infections result in no symptoms and other, entirely healthy people end up in the intensive care unit with respiratory failure and immune complications.

Influenza is not just a very bad cold. Between 12,00 and 60,000 Americans die of influenza every year. But, because COVID-19 is new and no one has natural immunity to it yet, it is even more dangerous, as evidenced by the 300,000+ Americans who have died from it in 2020.

Because there are so many unknowns, COVID-19 is in many ways more dangerous than the flu. At present, there is no effective vaccine available to society. Even after recovery from COVID-19, it is unclear how long immunity will last.

What to Do If You’re Sick

If you’re experiencing symptoms that are consistent with either COVID-19 or the flu, here are steps you can take to keep yourself and others safe:

Stay home and away from others

Avoid going out in public and try to separate yourself from any people or pets in your home. If possible, quarantine yourself in a separate room and use a different bathroom. Wear a mask if you need to be around others, even at home.

Get a COVID-19 test 

If you think you’ve been exposed to the coronavirus, we currently offer testing to those experiencing symptoms. If you may have been exposed but are asymptomatic, we recommend visiting our Sayre Health Center testing site in West Philadelphia or checking out your local health department website for more options.

Talk with your doctor

We currently offer telemedicine visits for all patients, especially those experiencing symptoms like fever or cough. Make a virtual appointment with your primary care physician (PCP), who can help diagnose your illness and the appropriate course of action to get you on the road to recovery.

If you are experiencing symptoms and are an older adult, are immunocompromised or have other conditions that make you vulnerable to COVID-19 or the flu, contact your doctor sooner rather than later. Seek medical care immediately if you are unusually short of breath—this could indicate low oxygen levels, possibly due to coronavirus.

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