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Cold, flu, or COVID-19: Which one is it?


November 8, 2021 | Healthy You | Wellness

young woman blowing nose into a tissue

Coughing? Fever? Chills? How can you tell if you have a cold, influenza, or COVID-19? Here's how they compare.

How can you tell if you have a cold, influenza, or COVID-19? Understanding the differences in symptoms that these illnesses cause will help.

Symptoms

Common colds, influenza (flu), and COVID-19 are contagious respiratory illnesses caused by different viruses. Many symptoms of the three are similar, which can cause confusion about which one you may be suffering from. Contact your primary care provider to determine what care you may need, including testing to determine which, if any, virus you have.  

  • COVID-19 is a highly contagious respiratory illness. COVID-19 can have varying degrees of symptoms, from none to severe. Symptoms may include fever or chills, severe cough, sore throat, and the loss of taste or smell. COVID-19 can cause medical complications, especially in higher-risk groups, and can result in hospitalization and death. Severe illness such as lung injury is more frequent with COVID-19 than with influenza. The mortality rate also is higher with COVID-19 than with the flu.
  • The flu is a contagious respiratory illness that can cause mild to severe illness, with symptoms such as fever, cough, and body aches. Like a fever, a bad headache is a hallmark of the flu, not a cold. So is fatigue, which can linger for weeks after your initial illness has passed. Most people with the flu don't need medical care or medication. However, the flu can be very serious and require medical attention. Contact your doctor if your symptoms worsen, are prolonged, or if you're at high risk of flu-related complications.
  • You may feel pretty crummy with a cold, but the symptoms are mild compared to viruses like the flu and COVID-19. Cold symptoms typically progress over seven to 10 days in this order: Sore throat, congestion, cough. Sniffling and sneezing is a classic cold symptom, and it's more common to experience a stuffy or runny nose with a cold than the flu. Rest, and many over-the-counter medications can help relieve symptoms.  

Here's how the three illnesses compare.

Cold vs Flu vs COVID-19 chart of symptoms

COVID-19 symptoms generally appear two to 14 days after exposure to SARS-CoV-2. Flu symptoms usually appear about one to four days after exposure to an influenza virus. Symptoms of a common cold usually appear one to three days after exposure to a cold-causing virus.

COVID-19 vs. Flu

So far, research indicates there may only be one significant difference in symptoms between COVID-19 and the flu:

  • The change in or loss of taste and smell.

Because of this, you may need to see a doctor for testing to determine which virus, if any, you have.

There are a few other notable similarities and differences between influenza and COVID-19.

How the viruses spread:

  • Similarities – both
    • can spread from person-to-person when they're within about 6 feet of each other.
    • spread mainly by respiratory droplets from someone who coughs, sneezes or talks. 
    • may be spread by people before they have symptoms, by people with very mild symptoms, and by people who never develop symptoms (asymptomatic).  
  • Differences: COVID-19 appears to be more contagious and to spread more quickly than the flu.

People at high risk:

  • Similarities: Both viruses can cause severe illness for older adults, people with certain underlying medical conditions, and pregnant women.
  • Differences:
    • The risk for complications for healthy children is higher with the flu. However, infants and children with underlying medical conditions are at increased risk for both flu and COVID-19.
    • Additionally, school-aged children with COVID-19 are at higher risk for Multisystem Inflammatory Syndrome in Children (MIS-C), a rare but severe complication of COVID-19.

Complications:

  • Similarities: Both COVID-19 and flu can cause these complications:
    • Pneumonia
    • Respiratory failure
    • Acute respiratory distress syndrome (fluid in the lungs)
    • Sepsis
    • Cardiac injury (heart attacks and stroke)
    • Multiple-organ failure (respiratory failure, kidney failure, shock)
    • Worsening of chronic conditions (involving the lungs, heart, or nervous system or diabetes)
    • Inflammation of the heart, brain, or muscle tissues
    • Secondary bacterial infections (infections in people who have already had the flu or COVID-19)
  • Differences: COVID-19 can also cause blood clots in the lungs, heart, legs or brain, and cause Multisystem Inflammatory Syndrome in Children (MIS-C)

Many people with the flu or mild symptoms of COVID-19 can recover at home with rest and fluids. But some people become seriously ill from the flu or COVID-19 and need hospital care.

Prevention

When possible, get a COVID-19 shot and an annual flu vaccination. You can also reduce your chance of getting or spreading COVID-19, colds, and the flu when you:

  • Avoid close contact (within 6 feet) with people who are sick.
  • Self-quarantine when you feel sick.
  • Wear a face mask in indoor public spaces and outdoors, such as at a crowded event or large gathering.
  • Avoid crowded indoor spaces.
  • Cover your mouth and nose with your elbow or a tissue when you cough or sneeze.
  • Avoid touching your eyes, nose, and mouth.
  • Wash hands often with soap and water for at least 20 seconds.
  • Clean and disinfect high-touch surfaces and objects.

Treatments

Cold. There's no cure for the common cold. Treatment may include pain relievers and over-the-counter cold remedies, such as decongestants. Most people recover from a common cold in three to 10 days, although some colds may last as long as two or three weeks.

Flu. Several antiviral drugs can be used to treat the flu. In addition, there are many over-the-counter remedies available. Getting an annual flu vaccine can also reduce the severity of the flu and the risk of serious complications. The vaccine can be given as a shot or as a nasal spray.

COVID-19. Unlike the common cold and the flu, only one antiviral drug, called remdesivir , is approved to treat COVID-19. Monoclonal antibody therapy treatment is available for people who have recently been diagnosed with COVID-19, have mild symptoms, and are at high risk of getting a severe infection. Doctors may also prescribe different medicines to help reduce the severity of COVID-19 and treat specific symptoms. Like the flu vaccine, getting one of the three approved COVID-19 vaccines can also reduce the severity of COVID-19 and the risk of serious complications.

If you have symptoms of the flu or COVID-19, contact your primary care provider to determine what care you may need, including testing to determine which, if any, virus you have.

The COVID-19 and flu vaccines are widely available at many community locations, including drug stores and pharmacies. Visit vaccines.gov to find a location near you.

Source: Centers for Disease Control and Prevention, Mayo Clinic

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