The quick comparison
| Symptom | Cold | Flu | COVID-19 |
|---|---|---|---|
| How it starts | Gradually, over a day or two | Suddenly, often within hours | Gradually or suddenly |
| Fever | Rare | Common, often high | Common |
| Body aches | Mild, if any | Common, often severe | Common |
| Tiredness | Mild | Common, can be extreme | Common, can last weeks |
| Runny or stuffy nose | Very common | Sometimes | Common |
| Sneezing | Very common | Sometimes | Sometimes |
| Sore throat | Very common | Sometimes | Common |
| Cough | Mild to moderate | Common, can be dry | Common |
| Headache | Sometimes | Common | Common |
| Loss of taste or smell | Occasionally, with a blocked nose | Rare | Possible, though less common than in early variants |
| Shortness of breath | Rare | Sometimes | Sometimes |
The pattern to remember: a cold is mostly in your nose and throat; flu feels like being hit by a truck; COVID can look like either.
When testing helps
Because symptoms overlap, a test is the only reliable way to tell flu from COVID.
- COVID self-tests (rapid antigen tests) are widely available. A single negative test early on can miss an infection, so many health authorities suggest testing again after 48 hours if symptoms continue.
- Combined flu and COVID tests are available from some pharmacies and clinics, and in some countries as home kits.
- Testing matters most if you are at higher risk of complications, or live with or visit someone who is, because flu and COVID antivirals work best when started early.
Treatment
For all three:
- Rest, and drink plenty of fluids. See how much water you need.
- Paracetamol (acetaminophen) or ibuprofen for fever, aches and sore throat, if safe for you. Our headache guide covers safe use.
- Honey and warm drinks for coughs and sore throats (not for babies under one year old).
- Saline sprays or steam for a blocked nose.
Antivirals:
- Flu: antiviral medicines such as oseltamivir can shorten illness and reduce complications, especially if started within 48 hours of symptoms. They are mainly prescribed to people at higher risk or who are seriously ill.
- COVID-19: antiviral treatments are available in many countries for people at higher risk of severe illness, and work best when started within the first few days.
Antibiotics do not work against any of these viruses. They are only useful if a bacterial complication develops, such as some pneumonias.
Who is at higher risk
Flu and COVID can be serious for:
- Adults aged 65 and over.
- Young children, especially under 5.
- Pregnant women.
- People with long-term conditions such as heart or lung disease, diabetes, kidney disease or a weakened immune system.
If you are in one of these groups and develop flu or COVID symptoms, contact a doctor or pharmacist early to ask about testing and antivirals.
When to get medical help
Get urgent help for:
- Difficulty breathing or shortness of breath at rest.
- Chest pain or pressure that does not go away.
- New confusion, or difficulty waking up.
- Bluish lips or face.
- Severe dehydration (very little urine, dizziness).
- Symptoms that improve and then come back worse, with fever and a worse cough.
- In children: fast or laboured breathing, not drinking, no tears when crying, or a fever with a rash.
See a doctor if symptoms last more than about 10 days, if you are at higher risk, or if you are worried.
How long you are contagious
- Cold: most contagious in the first two to three days of symptoms.
- Flu: from about a day before symptoms, and most contagious in the first three to four days.
- COVID-19: from a day or two before symptoms, and most contagious in the first few days. Many health authorities now advise staying home while you have a fever or feel unwell, then taking extra precautions such as masks around vulnerable people for a few days afterwards.
Prevention
- Get vaccinated. Annual flu vaccines and updated COVID vaccines reduce severe illness. See our flu vaccine guide for who should get one.
- Wash your hands often, and avoid touching your face.
- Stay home when sick, and cover coughs and sneezes.
- Improve ventilation indoors where you can.
- Consider a mask in crowded places during peak season if you are at higher risk.
Key takeaways
- Colds are mild and gradual; flu is sudden with fever and aches; COVID can look like either.
- Test if you need to know, especially if you are at higher risk.
- Antivirals help flu and COVID when started early; antibiotics do not help.
- Seek urgent care for breathing difficulty, chest pain or confusion.
This article is general information, not medical advice. Follow your local health authority's current guidance, and speak to a doctor or pharmacist if you are unwell.