Dealing with sniffles and a cough? Maybe feeling feverish? It’s not always easy to tell if you have a cold, the flu, or COVID-19. While these illnesses share some symptoms, they can vary in severity, risks, and recommended treatment.
Understanding the differences between these 3 respiratory illnesses helps you take the right steps to care for yourself and protect those around you.
Each illness at a glance
Common cold:
- Caused by many different types of viruses
- Usually mild and does not typically lead to serious health problems
- Comes on gradually
- Common symptoms are sore throat, mild cough, mild fatigue, and slight body aches
- Treat at home with over-the-counter medicines (guaifenesin, ibuprofen, acetaminophen); rest; and plenty of water
Influenza (flu):
- Caused by influenza viruses
- Can be mild or severe, sometimes leading to hospitalization
- Comes on quickly with more intense symptoms than a cold
- Common symptoms are fever, cough, fatigue, body aches, and headaches
- Treat at home with over-the-counter medicines (guaifenesin, ibuprofen, acetaminophen); rest; fluids to stay hydrated; and humidifiers and warm liquids to relieve sore throat and congestion
- For high-risk individuals, your doctor can prescribe antiviral medication like Tamiflu
- See your doctor if you have trouble breathing, chest pain, dizziness, confusion, persistent vomiting and trouble keeping liquids down, a fever of 103°F that doesn’t improve with medicine, or if your symptoms improve but then get worse
COVID-19:
- Caused by the SARS-CoV-2 virus
- Can range from mild to severe, with some patients at risk of long-term complications
- More likely than the cold or flu to cause a loss of taste or smell
- Common symptoms are fever, cough, fatigue, body aches, headaches, loss of taste or smell, and shortness of breath (in severe cases)
- Call a doctor if you experience trouble breathing, chest pain, confusion, difficulty staying awake, blue or gray skin, or symptoms that get worse after improving at first
- High-risk individuals, like those over 65 or with a chronic condition, should test as soon as they notice symptoms and reach out to their doctor to see if they can receive an antiviral treatment like Paxlovid
- If you have been exposed to Covid but don’t have symptoms, test 5 full days after your exposure
- Treat mild illness at home with rest, hydration, over-the-counter medicines (ibuprofen, acetaminophen, dextromethorphan, sore throat lozenges), and a humidifier or warm steam for congestion relief
No matter what illness you think you have, if you are experiencing difficulty breathing, a persistent high fever, chest pain or pressure, confusion, trouble staying awake, or symptoms that worsen after initial improvement, call your Marathon Health provider. Always seek emergency care for severe symptoms.
Prevention tips: protect yourself and others
Whether it’s the cold, the flu, or COVID, you can reduce the spread of respiratory viruses with these everyday habits:
- Wash your hands often: Wash with soap and warm water for at least 20 seconds. Don’t forget to wash between your fingers, under your nails, and the backs of your hands!
- Use hand sanitizer: Apply hand sanitizer with at least 60% alcohol when soap and water aren’t available.
- Cover coughs and sneezes: Use your elbow or a tissue to prevent the spread of germs.
- Avoid close contact: Keep your distance from others who are sick.
- Stay home if you’re sick: Prevent spreading illnesses by reducing your exposure to others. If you must be out, wear a mask to protect others.
Keep clean: disinfect frequently touched surfaces.
Stay protected with vaccines
Vaccination is one of the best ways to protect yourself and those around you from serious illness. Vaccines help prevent severe illness, hospitalization, and death.
- Annual flu vaccines are recommended for everyone 6 months and older
- COVID-19 vaccines and booster shots are recommended for most adults 18 years old and older
You can talk with your Marathon Health provider about staying up to date on your flu vaccines and where you can get a COVID vaccination.
Marathon is here to help
If you’re feeling sick but don’t know what’s causing your symptoms, your Marathon Health provider is here to help and recommend next steps.
Sources:
Centers for Disease Control and Prevention. (n.d.). Guidance for respiratory viral illnesses. https://www.cdc.gov/respiratory-viruses/guidance/index.html
Centers for Disease Control and Prevention. (2025, June 6). Staying up to date with COVID-19 vaccines. https://www.cdc.gov/covid/vaccines/stay-up-to-date.html
Centers for Disease Control and Prevention. (2025, August 18). Preventing respiratory illnesses. https://www.cdc.gov/respiratory-viruses/prevention/index.html
Centers for Disease Control and Prevention. (n.d.). Tools & resources for respiratory viral illnesses. https://www.cdc.gov/respiratory-viruses/tools-resources/index.html
Centers for Disease Control and Prevention. (2024, August 8). Cold versus flu. https://www.cdc.gov/flu/about/coldflu.html
Centers for Disease Control and Prevention. (2024, September 17). Similarities and differences between flu and COVID-19. https://www.cdc.gov/flu/about/flu-vs-covid19.html