COVID-19, cold, allergies and the flu: What are the differences?

Date Updated: 11/27/2024

Coronavirus disease 2019 (COVID-19) can cause many of the same symptoms as the common cold, seasonal allergies and the flu. So how can you tell if you have COVID-19?

It may help to learn about the differences in symptoms that these illnesses cause. Also, find out how these illnesses spread, are treated and can be prevented.

The only way to find out for sure if you have COVID-19 is to get tested right away. If you have symptoms of the disease, you can use a COVID-19 test kit at home. Or contact your healthcare professional. Describe how you feel and ask how you should get tested.

What is COVID-19, how does it spread and how is it treated?

COVID-19 is a respiratory disease that spreads from person to person. It's caused by an infection with the virus SARS-CoV-2. The virus usually spreads between people who are in close contact. It passes through droplets released when an infected person breathes, coughs, sneezes, talks or sings. These droplets can land in the mouth or nose of someone nearby or be breathed in. The virus also can spread if you touch a surface or object with the virus on it and then touch your mouth, nose or eyes. But this risk is low.

The most common symptoms of COVID-19 have changed over time. Currently, they are runny or stuffy nose, headache, and sore throat. But there are many other possible symptoms, such as fever, a cough and tiredness. Many people with COVID-19 have mild illness. But the disease can cause serious illness and complications. For some people, it can be life-threatening.

Treatment for mild illness includes resting at home. Medicines such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others) can ease fever and discomfort. In the United States, the Food and Drug Administration has approved a few medicines to treat COVID-19. Researchers are testing a variety of possible treatments. No cure is available for COVID-19. Medicines called antibiotics that clear up infections from bacteria don't work against viral infections such as COVID-19.

What's the difference between COVID-19 and the common cold?

Both COVID-19 and the common cold are caused by viruses. COVID-19 is caused by SARS-CoV-2. The common cold most often is caused by rhinoviruses. All of these viruses spread in similar ways and cause many of the same symptoms. But there are a few differences.

Symptom check: Is it COVID-19 or a cold?
Symptom	COVID-19	Cold
Headache	Usually	Rarely
Cough	Sometimes (dry)	Sometimes
Muscle aches	Sometimes	Never
Tiredness	Usually	Never
Sneezing	Sometimes	Sometimes
Sore throat	Usually	Usually
Runny or stuffy nose	Usually	Usually
Fever	Sometimes	Rarely
Diarrhea	Sometimes	Usually
Nausea or vomiting	Sometimes	Sometimes
Shortness of breath or trouble breathing	Sometimes	Never
New loss of taste or smell	Sometimes (early — often without a runny or stuffy nose)	Never

COVID-19 symptoms usually start 2 to 14 days after exposure to SARS-CoV-2. But symptoms of a common cold usually appear 1 to 3 days after exposure to a cold-causing virus.

There's no cure for the common cold. Treatment may include pain relievers and cold remedies available without a prescription, such as decongestants. Unlike COVID-19, a cold is usually harmless. Most people get better from a common cold in 3 to 10 days. But some colds may last as long as two weeks.

What's the difference between COVID-19 and seasonal allergies?

Unlike COVID-19, seasonal allergies aren't caused by a virus. Seasonal allergies are immune system responses triggered by exposure to allergens, such as seasonal tree or grass pollens.

COVID-19 and seasonal allergies can cause many of the same symptoms. But there are some differences.

Symptom check: Is it COVID-19 or seasonal allergies?
Symptom	COVID-19	Allergy
Headache	Usually	Rarely
Cough	Sometimes (dry)	Sometimes
Fever	Sometimes	Never
Muscle aches	Sometimes	Never
Tiredness	Usually	Sometimes
Itchy nose, eyes, mouth or inner ear	Sometimes	Usually
Sneezing	Sometimes	Usually
Sore throat	Usually	Sometimes
Runny or stuffy nose	Usually	Usually
Pink eye, also called conjunctivitis	Sometimes	Sometimes
Nausea or vomiting	Sometimes	Never
Diarrhea	Sometimes	Never
Shortness of breath or trouble breathing	Sometimes	Sometimes
New loss of taste or smell	Sometimes (early — often without a runny or stuffy nose)	Sometimes

COVID-19 can cause shortness of breath or trouble breathing. But seasonal allergies usually don't cause these symptoms. That's unless you have a breathing-related condition such as asthma that can be triggered by pollen exposure.

Treatment of seasonal allergies may include:

Medicines called antihistamines that block a chemical made by the immune system during an allergic reaction.
Medicines called decongestants that can ease nasal and sinus congestion for a short time.
Nasal steroid sprays that prevent and relieve stuffiness.
Staying away from allergens that trigger your symptoms whenever possible.

Seasonal allergies may last for weeks.

What's the difference between COVID-19 and the flu?

COVID-19 and the flu are both respiratory diseases that spread from person to person. They're also both caused by viruses. COVID-19 is caused by the SARS-CoV-2 virus. The flu is caused by influenza A, B and C viruses. All of these viruses spread in similar ways.

COVID-19 and the flu cause many of the same symptoms, but there are some differences. The diseases also can cause no symptoms or cause mild or severe symptoms. Because the symptoms can overlap, testing may be done to see if you have COVID-19 or the flu. You also can have both diseases at the same time.

**Symptom check: Is it COVID-19 or the flu?**
Symptom	COVID-19	Flu
Headache	Usually	Usually
Cough	Sometimes (dry)	Usually
Muscle aches	Sometimes	Usually
Tiredness	Usually	Usually
Sneezing	Sometimes	Sometimes
Sore throat	Usually	Usually
Runny or stuffy nose	Usually	Usually
Fever	Sometimes	Usually
Nausea or vomiting	Sometimes	Sometimes (more common in children)
Diarrhea	Sometimes	Sometimes (more common in children)
Shortness of breath or trouble breathing	Sometimes	Sometimes
New loss of taste or smell	Sometimes (early — often without a runny or stuffy nose)	Rarely

COVID-19 symptoms usually start 2 to 14 days after exposure to SARS-CoV-2. Flu symptoms usually appear about 1 to 4 days after exposure to an influenza virus.

COVID-19 can cause more-serious illnesses in some people than can the flu. Also, COVID-19 can cause different complications from those of the flu.

Medicines called antivirals can help the body fight off viruses. A few have been approved to treat COVID-19, and others are approved to treat the flu.

How can you lower your risk of COVID-19, a cold and the flu?

If you are at a higher risk of serious illness from COVID-19 or the flu, talk to your healthcare professional about how best to protect yourself. Know what to do if you get sick so you can quickly start treatment.

You can lower your risk of infection with viruses that cause COVID-19, the flu, or colds by following some standard safety measures.

Get vaccinated

Get a yearly flu vaccine and stay up to date with the COVID-19 vaccine. The COVID-19 vaccine can lower the risk of death or serious illness caused by COVID-19. The Centers for Disease Control and Prevention recommends a COVID-19 vaccine for everyone age 6 months and older.

Getting a yearly flu vaccine lowers your risk of the flu. It can be given as a shot or as a nasal spray. The flu vaccine also lowers the chance you'll have a serious case of flu. It also lowers the risk of serious complications.

Wash your hands often and follow good hand hygiene

Use soap and water and scrub for at least 20 seconds. Or use an alcohol-based hand sanitizer that contains at least 60% alcohol.

Wash your hands well and often with soap and water for at least 20 seconds. If soap and water aren't available, use an alcohol-based hand sanitizer with at least 60% alcohol. Make sure friends and family that you're around regularly, especially kids, know the importance of hand-washing.

Cover your mouth and nose with the inside of your elbow or a tissue when you cough or sneeze. Throw away the used tissue. Wash your hands right away.

Try not to touch your eyes, nose, and mouth.

Regularly clean and disinfect high-touch surfaces

Regularly clean often-touched surfaces to prevent spread of infection from touching a surface with the virus on it and then your face. Examples of high-touch surfaces include doorknobs, light switches, electronics, and counters.

Be cautious in indoor public spaces

Try to keep distance between yourself and others when you're in these spaces. This is especially important if you have a higher risk of serious illness. Some people with COVID-19 can spread the COVID-19 virus to others even if they don't have symptoms. They might not know that they have COVID-19.

Stay away from crowded indoor spaces and indoor places that have poor airflow. Respiratory viruses spread more easily in crowded indoor spaces, especially ones that have poor airflow. If you need to be in these spaces, it can help to wear a mask and improve the airflow.

To lower your chance of catching the virus that causes COVID-19, keep indoor air moving. That means open windows if possible. Turn on fans to direct air out of windows. If you can't open windows, consider using air filters. And turn on exhaust fans in your bathroom and kitchen. You also might consider a portable air cleaner.

Wearing a facemask

The CDC recommends that people wear a mask in indoor public spaces if you're in an area with a high number of people with COVID-19 in the hospital. They suggest wearing the most protective mask possible that you'll wear regularly, that fits well and is comfortable.

The CDC suggests that people who are diagnosed with flu or suspect they have flu consider wearing a facemask around others. This means wearing a facemask around members of your household and when you go for medical care. People who are not ill and choose to wear a mask can get the best protection by wearing a mask every time they are in public and at home when around others.

Limit contact during illness

Stay away from anyone who is sick. Try not to have close contact with anyone who seems ill or has symptoms.

If you have symptoms of COVID-19, test for the infection. Or test five days after you came in contact with the virus.

If you're sick, stay home and away from others, including pets, if possible. Don't use public transportation, taxis, and ride-hailing services if you're sick. Don't share dishes, glasses, towels, bedding, and other household items if you're sick.

How can you prevent allergies?

The best way to prevent seasonal allergies is to stay away from your known triggers. If you're allergic to pollen, stay inside with windows and doors closed when there's a lot of pollen in the air.

Wearing a face mask also might provide some protection against seasonal allergies. Masks can prevent you from breathing in some larger pollen particles. But smaller pollen particles can get through a disposable face mask. It's important to wash a reusable mask after each use since a mask might carry pollen particles.