A sore throat, cough and runny nose could be a lot of things. Colds, the flu and COVID-19 are all caused by viruses that infect the respiratory tract, and their symptoms overlap a lot. Knowing the typical differences can help you decide what to do next, but because they look so similar, testing is often the only way to know for sure.
The common cold
- Onset: gradual
- Typical symptoms: runny or stuffy nose, sneezing, sore throat, mild cough
- Fever: uncommon in adults
- How you feel: usually able to go about your day
- Duration: about 7 to 10 days
Colds are caused by many viruses, most often rhinoviruses. They’re usually mild and rarely lead to serious complications.
The flu (influenza)
- Onset: sudden, often within hours
- Typical symptoms: fever or chills, body aches, headache, extreme tiredness, dry cough, sore throat
- How you feel: often wiped out and in bed
- Duration: most people feel better in a few days to two weeks, though tiredness can linger
Flu can lead to serious complications such as pneumonia, especially in young children, older adults, pregnant people and people with chronic conditions.
COVID-19
- Onset: varies, often 2 to 5 days after exposure
- Typical symptoms: cough, sore throat, fever, fatigue, body aches, headache, congestion; sometimes loss of taste or smell (less common now than earlier in the pandemic)
- How you feel: ranges from very mild to severe
- Duration: often a week or two; some people develop long COVID
Why testing matters
Because symptoms overlap so much, you usually can’t tell flu from COVID-19 by symptoms alone. Testing matters because antiviral treatments for both flu and COVID-19 work best when started early, within the first few days of symptoms, especially for people at higher risk. Home tests are widely available, including combination tests for both viruses. Learn more about testing at home.
When to see a doctor
Contact a healthcare provider early if you’re at higher risk of complications, such as being 65 or older, pregnant, having a chronic condition like asthma, diabetes or heart disease, or having a weakened immune system. You may benefit from antiviral medicine.
Seek emergency care for trouble breathing, chest pain or pressure, confusion, inability to stay awake, bluish lips or face, severe dehydration, or symptoms that improve and then return with fever and worse cough.
What this means for you
If you feel sick, stay home, rest and test. Most colds, flu and COVID-19 cases can be managed at home. See our guide to caring for flu or COVID-19 at home. Staying up to date on recommended vaccines, washing your hands and staying home when sick help protect you and others.
The bottom line
Colds are usually mild and come on gradually. Flu tends to hit suddenly with fever and body aches. COVID-19 varies widely. Because they overlap so much, testing is the best way to know which one you have, and early treatment can help people at higher risk.
Common questions
Can you have flu and COVID-19 at the same time?
Yes. It’s possible to be infected with both, which can cause more severe illness. A combination test can check for both.
Do antibiotics help colds, flu or COVID-19?
No. Antibiotics don’t work against viruses. They’re only used if a bacterial infection, such as bacterial pneumonia, develops.
How long are flu and COVID-19 contagious?
People are usually most contagious in the first few days of illness, but can spread both viruses before symptoms start. Staying home while sick and until your fever is gone helps protect others.
This article is for general information and isn’t medical advice. Talk with your healthcare provider about your individual needs.
