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Is It Allergies, a Cold, the Flu, or COVID-19?

Since COVID-19 began spreading, the public has often tried to compare it with the flu. Finding similarities in something we are trained to recognize can be reassuring when you’re fighting an invisible enemy.

But how alike are COVID-19 and other common respiratory and sinus-related diseases, really? We took a closer look, comparing and contrasting a few diseases with information available through the Centers for Disease Control and Prevention. Here’s what we know.

Infographic about differences between allergies, cold, flu and COVID-19


Similarities: Symptoms range from no symptoms (asymptomatic) to severe symptoms. Common symptoms for COVID-19 and the flu include fever or feeling feverish/chills, cough, shortness of breath or difficulty breathing, sore throat, fatigue, runny or stuffy nose, muscle pain or body aches, headaches, vomiting and diarrhea. The common cold sometimes includes fatigue, fevers, and aches. Generally, allergies lead to symptoms of sneezing, itchy eyes/nose, and runny or stuffy nose.

Differences: Allergy symptoms can appear at any time and can last from days to months, depending on the cause. Flu and common cold symptoms appear more quickly, usually within one to four days. COVID-19 symptoms may not appear for two to 14 days after exposure to the virus. A unique symptom of COVID-19 is change in or loss of taste or smell.

Vaccinations have shown to greatly reduce symptoms in breakthrough cases of COVID-19. It is important to note that new symptoms are arising, and not all symptoms are always present, according to the Ohio Department of Health. If you feel sick, stay home and call your doctor.


Similarities: Everyone is susceptible to any of the conditions and viruses. Older adults, those with other health conditions and pregnant people are at a higher risk of developing severe symptoms and are at an increased risk for COVID-19 and influenza.

Differences: School-aged children infected with COVID-19 are at higher risk of Multisystem Inflammatory Syndrome in Children (MIS-C), which is a rare but severe COVID-19 complication.


Similarities: Common complications for COVID-19 and the flu include pneumonia, respiratory failure, acute respiratory distress syndrome, sepsis, cardiac injury, multiple-organ failure, worsening of chronic medical conditions, inflammation of the heart, brain or muscle tissues, and secondary bacterial infections. With the common cold, complications can include ear pain/infection, fever, and asthma flare-ups.

Differences: COVID-19 has also been associated with blood clots in the veins and arteries of the lungs, heart, legs or brain, as well as Multisystem Inflammatory Syndrome in Children (MIS-C).


Similarities: Transmission of COVID-19, the flu and the common cold seems to be almost identical. Both diseases are spread easily from person to person through small respiratory droplets containing the virus. These droplets appear when someone coughs, sneezes or even talks. It’s also possible that a person can contract the virus by touching surfaces where these droplets land and then touching their eyes, nose or mouth.

You can spread any of the three to others without being aware you are infected. It’s important to follow recommendations to stop the spread, like mask-wearing, social distancing and hand hygiene.

For the common cold, the flu and COVID-19, practicing good hygiene can help prevent the spread.

Differences: While is seems COVID-19 and the flu spread in similar ways, COVID-19 is more contagious amongst certain age groups and populations. COVID-19 can spread quickly and easily to a lot of people, resulting in higher continuous spread than with the flu. The length of time someone with COVID-19 is able to spread the virus is still being reviewed but is generally believed to be 2 days prior to symptoms up to 10 days after symptoms appear, while someone with the flu is contagious from one day prior to symptoms appearing up until 7 days after symptoms appear. Infants and those who are immunocompromised can be contagious for longer periods of time.

Allergies cannot spread from person to person. There may be common triggers for people but symptoms and experiences depend on the individual.


Similarities: The actions we take to prevent the flu and common cold work against COVID-19 as well. These include frequent hand hygiene, mask-wearing, social distancing, disinfecting surfaces, and covering coughs and sneezes with a tissue or sleeve.

Differences: A new flu vaccine comes out each year to help prevent infection. In the US, there are currently two vaccines authorized by the FDA and one FDA approved COVID vaccine. Boosters are now approved for Pfizer and Moderna vaccines.


Similarities: We can test for the flu and COVID-19 to confirm infections.

The CDC advises the following people should get tested for COVID-19:

  • People who have symptoms of COVID-19.
  • People who have come into close contact with someone with COVID-19:
    • Fully vaccinated people should be tested 5–7 days after their last exposure.
    • People who are not fully vaccinated should get tested immediately when they find out they are a close contact. If their test result is negative, they should get tested again 5–7 days after their last exposure or immediately if symptoms develop.

Differences: There are no specific tests to detect a common cold or allergies. Comparing and contrasting symptoms or eliminating the possibility of other possibilities, such as influenza or COVID-19, can help determine a diagnosis of cold or allergies.


Similarities: Some over-the-counter medications, such as acetaminophen, can be used to manage symptoms of any of the conditions discussed above. Antibiotics should not be used to prevent or treat the flu, COVID-19 or other viruses, like the common cold.

Differences: There are antiviral medications that can shorten the duration of the flu, ease symptoms and prevent complications.

Monoclonal Antibody Therapy has been approved by the FDA under emergency use authorization for the treatment of mild to moderate cases of COVID-19. To stay up to date, the National Institutes of Health (NIH) regularly updates guidance on treatment.

For allergies, consider an allergy medication, such as Zyrtec or Claritin D, to help manage symptoms.

Infection and mortality rates

Similarities: The common cold and allergies are significantly more common than COVID-19 or the flu, but the mortality rates for those conditions are essentially nonexistent. While the majority of flu and COVID-19 cases are mild, some do result in death

Differences: Each year in the United States, the average adult will have 2-3 colds and children even more than that. For allergies, approximately eight percent of Americans experience it each year.

COVID-19 mortality rates have changed tremendously since the roll out of vaccines and widespread use of monoclonal antibodies. As of now, greater than 90 percent of COVID deaths are in unvaccinated people. People who contract COVID and are vaccinated are significantly less likely to die.

Anthony S. Fauci, the director of the National Institute of Allergy and Infectious Diseases, says the flu’s mortality rate is 0.1%. This would make COVID-19 16 times more lethal than the flu.

If you think you may have come into contact with someone who has COVID-19, call your primary care doctor or the Ohio Department of Health call center. The call center is now open seven days a week from 9 a.m. to 8 p.m. to answer your COVID-19 questions, and can be reached at 1 (833) 4-ASK-ODH (1 (833) 427-5634).

The information in this article was updated on August 31, 2021. For the latest information concerning…

Go to COVID-19 Toolkit page on OhioHealth blog


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