What is a Cold? What is Flu?

what is cold

Colds and flu are both illnesses caused by viruses. Through laboratory research, scientists have found three different viruses that can cause flu, but over 200 different viruses that can cause a cold - sometimes referred to as a "common cold". Colds and flu can affect all ages, from babies to the elderly.

How to tell the difference between cold and flu

Without the help of scientific laboratory tests, it can sometimes be very difficult to tell which is which. This is because, although their symptoms do have some differences, there are a lot of similarities too. So let's take a look at them:

Cold symptoms

Flu symptoms

Runny nose - with clear mucus at first then thicker, green mucus as the cold progresses

Fever - that may come on suddenly - body temperature can go up to 37.8-40⁰C (100-104⁰F)

Blocked nose



Cough - a dry, chesty cough


Extreme tiredness or exhaustion. Sufferers may feel the need to lie down and rest

Sore throat

Runny nose, sneezing

Fever, tiredness, muscles aches

A headache

A headache



One other key difference is the impact of seasonality. While Flu tends to be seasonal - during the winter months, Colds can be experienced throughout the year. The reason for this is that flu viruses need different conditions to survive and multiply compared with cold viruses. Also, Flu viruses seem to survive longer in dry, cold, winter air.

Why is it important to know whether it is a cold or the flu?

Since you may not get all the symptoms at the same time, and also because you can suffer the symptoms to different degrees, telling the colds and flu apart can become even more challenging. For example, colds may be called "mild" or "heavy" colds and a heavy cold may feel more like flu. In children and the elderly it is important to recognise the flu as these people are at more at risk of complications compared to the rest of the population.

How to treat colds and flu in children between 3 months (and weighing over 5kg) and 12 years?


  • Hydrate, eat healthily: If your child does fall ill with a cold or the flu, it's important to keep them hydrated by giving them plenty of cool water to drink. Even if your child isn't thirsty, try to get them to drink little and often to keep their fluid levels up. Your child might lose their appetite, they should still eat small portions of low-fat, high fibre ingredients such as fruits and vegetables.
  • Check clothing: Dress your child appropriately for their surroundings. It’s important they are not underdressed or overdressed when suffering a fever.
  • Consult doctor