What’s the difference between a cold, flu or COVID?
Little. And you cannot tell the difference as the symptoms of all three are the same; as they are all respiratory viruses – and spread in the same way (coughing etc):
- Blocked or runny nose
- Sore throat or earache
- Headache
- Muscle aches
- Cough
- Sneezing
- Fever
- Pressure in your face
- Loss of taste and smell.
What is the difference between a cold, flu and COVID-19?
They are similar. Influenza (flu), the common cold, and COVID-19, are all contagious respiratory viral illnesses – but caused by different viruses.
Flu is caused by influenza viruses only. Whereas the common cold can be caused by a number of different viruses, including rhinoviruses, parainfluenza, and seasonal coronaviruses. The latter should not be confused with SARS-CoV-2, the virus that causes COVID-19.
Because all three have similar symptoms, it can be difficult to distinguish them based on symptoms alone. In general, flu is worse than the common cold, and symptoms are typically more intense and begin more abruptly.
Colds and COVID-19 are usually milder than flu. People with colds are more likely to have a runny or stuffy nose than people who have flu. Colds generally do not result in serious health problems, such as pneumonia, bacterial infections, or hospitalisation. Flu and COVID-19 can have serious complications.
Who should have a test to make a certain diagnosis?
As colds, flu and COVID-19 share so many symptoms, it can be difficult (or even impossible) to tell the difference between them based on symptoms alone.
Fortunately most people with mild versions of all three, do not need a definitive test to make a certain diagnosis; as you will get better with no treatment. Though two sub-groups need some form of test:
- Suspected flu – if you are seriously unwell and in hospital, blood tests may be needed. They are not reliable, partly as flu can be due to so many different viruses. And these change (and evolve) every year
- Suspected COVID-19 – e.g. if you have had contact with someone with COVID-19, or are a health or social care professional where you may be in danger of infecting patients or clients you care for. You may then need a throat swab – either lateral flow test (LFT) or PCR.
For a common cold, there is no test anyway; again partly as they can be due to so many different viruses. And again, the viruses change (and evolve) every year.
Allergies
Oh yes. Some allergies can also cause a runny nose and sneezing. But they’re not contagious. If your eyes, nose, or ears itch, that could also be an allergy. Exposure to things like dust, pets, and tree or grass pollen can trigger allergies; which are caused by the immune system over-reacting.
Summary
We have explained whats the difference between a cold, flu or COVID. Not much, in terms of symptoms. They are impossible to distinguish on symptoms alone.
