Colds build gradually with a runny nose, sneezing and sore throat. Flu strikes fast with fever, aching muscles and exhaustion. COVID-19 can look like either and may cause loss of smell or taste. Symptoms alone cannot always tell them apart; only a test can confirm.

That limit matters. A cough, a temperature and a headache could be any of the three, and even experienced clinicians cannot always separate them by symptoms alone. This guide sets out the usual differences, what a pharmacist can help with, and the signs that mean you need a GP, NHS 111 or 999.

The short answer

If you want a quick way to think about the difference between cold and flu (and where COVID-19 fits), use these three rules of thumb:

• Speed: a cold creeps in over a day or two. Flu usually hits within hours.
• Severity: a cold is a nuisance. Flu often leaves you in bed. COVID-19 can be mild or severe.
• Smell and taste: a lost or changed sense of smell or taste points more towards COVID-19, although a heavily blocked nose can dull both.

These are patterns, not a diagnosis. The table below shows how they play out symptom by symptom.

Cold vs flu vs COVID symptoms side by side

Symptom	Cold	Flu	COVID-19
How it starts	Gradually, over a day or two	Suddenly, often within hours	Gradually or suddenly
Fever or high temperature	Uncommon, usually mild	Common, often high	Common
Aches and pains	Mild, if any	Common, can be severe	Common
Tiredness	Mild	Common, can be extreme	Common, can be marked
Runny or blocked nose	Very common	Sometimes	Sometimes
Sneezing	Common	Less common	Less common
Sore throat	Common	Sometimes	Sometimes
Cough	Mild to moderate	Common, usually dry	Common, can be persistent
Headache	Uncommon	Common	Common
Loss or change of smell or taste	Rare (a blocked nose can dull it)	Rare	More common
Shortness of breath	Rare	Possible in severe cases	Possible
Feeling sick or diarrhoea	Rare	Sometimes, more often in children	Sometimes

This is a general guide based on how these illnesses are described by the NHS. Everyone is different, and COVID symptoms in the UK now overlap heavily with colds and flu. Which symptoms are most common can also shift as new variants spread.

If a sore throat is your main complaint, our guide to sore throat symptoms and when to get treatment explains the usual causes and what helps.

How quickly it starts and how long it lasts

Colds

A cold usually starts with a sore throat or a tickly nose, followed by a runny or blocked nose, sneezing and a cough. Symptoms tend to peak after two or three days. Most people feel better within one to two weeks, although a cough can linger a little longer. A fever is uncommon in adults and more likely in children.

Flu

Flu comes on suddenly. Within hours you can go from feeling fine to having a fever, chills, aching muscles and deep tiredness. Most people start to improve after about a week, but tiredness and a cough can hang around for a couple of weeks. Flu can also lead to complications such as chest infections and pneumonia, particularly in older adults, pregnant women and people with long-term health conditions.

COVID-19

COVID-19 can start gradually or suddenly, and the symptoms range from very mild to severe. Most people recover within a couple of weeks, although a cough and tiredness can last longer. It can be more serious for older adults and for people with weakened immune systems or long-term conditions.

Why symptoms alone are not always enough

There are several reasons it is hard to tell these illnesses apart at home:

• The symptoms overlap. Fever, cough, aches and tiredness can appear in all three.
• Symptoms vary by person. Children, older adults and people with weakened immune systems can have unusual or milder symptoms. An older person with flu, for example, may not have a high temperature.
• You can have more than one at once. Catching two infections together, or one soon after the other, is possible.
• Testing is how you confirm COVID-19. A COVID-19 test can confirm it, but free testing is no longer widely available to the general public in the UK. Tests can be bought from many pharmacies and shops. Flu is usually recognised from symptoms during flu season, and lab testing is mostly used in hospital or for people at higher risk.

In practice, it is often better to respond to how unwell you are and how at-risk you or your household are, rather than worrying about the exact label. If you are unsure, act as though you could be infectious: rest, stay home while you have a fever and avoid close contact with anyone vulnerable.

What a pharmacist can help with

A pharmacist is a good first stop for colds, flu-like illness and cough. You do not need an appointment for general advice, and they can:

• Talk through your symptoms and help you decide whether self-care is enough or you should see someone else.
• Recommend suitable relief for fever, aches, a blocked nose, sore throat and cough, and check that it is safe alongside any other medicines you take. This matters if you are pregnant, have asthma, high blood pressure, or kidney or stomach problems.
• Advise on children’s medicines. Many over-the-counter cough and cold products are not suitable for young children, so always ask first.
• Assess a sore throat. Under the NHS Pharmacy First service, a pharmacist may be able to assess and treat a sore throat in people aged 5 and over without a GP appointment. Pharmacy First does not cover colds or flu themselves, but our guide to what your pharmacist can treat under NHS Pharmacy First shows which conditions it does.
• Point you to the right place. If your symptoms sound like something more, a pharmacist will tell you so. Our article on deciding between a GP visit and a pharmacy consultation is a useful read if you are unsure.

Warning signs: GP, NHS 111 or 999

Most colds and many cases of flu can be managed at home. These signs mean you should get help.

Call 999 or go to A&E if you or your child:

• Are struggling to breathe, or cannot speak in full sentences
• Have chest pain or tightness
• Have blue, grey or very pale lips, skin or tongue
• Are suddenly confused, very hard to wake or have a seizure
• Have a high temperature with a stiff neck, or a rash that does not fade when a glass is pressed against it
• Are coughing up blood

Call NHS 111 (or use 111 online) if:

• You are unsure how serious things are
• You are getting worse rather than better
• A baby under 3 months has a temperature of 38°C or higher
• A child is unusually drowsy, drinking much less than normal or has noticeably fewer wet nappies

Contact your GP if:

• Flu-like symptoms have not improved after about a week
• A cough or other symptoms have lasted more than three weeks
• You are 65 or over, pregnant, or have a long-term condition (such as asthma, diabetes, or heart, lung or kidney disease) or a weakened immune system and develop flu-like symptoms. Contact your GP early, as they can advise on whether treatment is appropriate.

Protecting people at home

Whichever virus it is, the same simple steps reduce the chance of passing it on:

• Stay home while you have a fever or feel too unwell for normal activities.
• Catch coughs and sneezes in a tissue, bin it straight away and wash your hands.
• Wash hands often, especially before eating and after blowing your nose.
• Open windows when you can for fresh air, and clean shared surfaces such as door handles.
• Avoid sharing cups, towels and cutlery.
• Keep away from anyone who is elderly, pregnant or has a weakened immune system. If you must be around others, consider wearing a face covering.
• Rest and drink plenty of fluids.

For people who are eligible, vaccination is the best protection against flu and COVID-19, and the two can often be given at the same appointment. Our guide to flu and COVID vaccines together explains what to expect.

If you are in an eligible group this autumn

The NHS offers free flu and COVID-19 vaccines to people at higher risk of becoming seriously ill. Who qualifies can change from year to year, so check the latest criteria in our article on who is eligible for the free NHS flu vaccine.

If you are not eligible for an NHS jab but would like protection, a private option is available at Burnham Health Pharmacy. You can find out more on our flu vaccination service page, and the team can also talk you through COVID-19 vaccination options.

FAQ

What is the difference between cold, flu and COVID symptoms?

Colds are usually mild and start gradually with a runny or blocked nose, sneezing and a sore throat. Flu comes on suddenly with fever, body aches and extreme tiredness. COVID-19 can cause any of these symptoms and may also cause a loss or change of smell or taste. Because they overlap, symptoms alone cannot always tell them apart.

Can you have flu and COVID together?

Yes. It is possible to catch both at the same time, or one soon after the other. Having both can make you feel more unwell, so if you are in a higher-risk group or symptoms are getting worse, speak to your GP or call NHS 111 for advice.

How long should I stay home?

There is no single rule for every illness. If you have a fever or feel too unwell for your normal activities, stay home until you feel better and avoid contact with vulnerable people. For COVID-19, current UK guidance says adults who test positive should try to stay home and avoid contact with others for 5 days, and children and young people for 3 days. Guidance can change, so check the NHS website for the latest advice.

Is it a cold or flu if I have a fever?

A sudden, high fever with aching muscles and exhaustion points more towards flu than a cold. A mild temperature can still happen with a cold, particularly in children, and fever is also common with COVID-19. If you are unsure whether it is a flu or cold, a pharmacist can talk through your symptoms.

When should I see a pharmacist for a cold?

Speak to a pharmacist if your symptoms are bothering you and you want to know which medicines are suitable, if you take other medicines, are pregnant or have a long-term condition, or if the cold is in a child. It is also worth asking if you have a sore throat that is not improving or you are not sure whether it is something more than a cold.

Quick decision list: if this, then that

• Runny nose, sneezing, mild sore throat, and otherwise feeling fine? Probably a cold. Rest, drink fluids and ask a pharmacist about symptom relief.
• Sudden fever, aching body and exhaustion? Probably the flu. Stay home, rest and drink fluids. If you are in a higher-risk group, contact your GP early.
• Loss of smell or taste, or flu-like symptoms after contact with someone with COVID-19? Consider a COVID-19 test and stay home until you feel better.
• Not sure which it is? Ask a pharmacist. They can talk through your symptoms and tell you whether you need more help.
• Symptoms worsening, a baby with a fever, or a child who is drowsy or not feeding or drinking? Call NHS 111 or your GP.
• Struggling to breathe, chest pain, blue lips or sudden confusion? Call 999.

Not sure what you are dealing with? Phone Burnham Health Pharmacy on 01628 603 170 or pop in to 30 High Street, Burnham, SL1 7JP. Our pharmacists are happy to help, and you can find out about our walk-in services or get in touch online.