Colds & Flu: What to Know

What is the difference between a cold and the flu? Who is at most risk? We are glad you asked. Find all this and more.

Flu at a Glance

Colds & Flu: What to KnowCause: Influenza (flu) is caused by a virus. There are three main types of influenza virus:

  • Type A: These viruses are responsible for most cases of human flu. There are many subtypes (e.g. H1N1). Some can cause epidemics. Some cause disease in animals, such as birds, pigs and horses.
  • Type B: These viruses are less common and usually cause less severe illness, but can sometimes cause outbreaks of flu – particularly amongst children.
  • Type C: These viruses usually only cause mild flu and are rare.
  • Spread: Flu spreads by inhaling the droplets that are expelled from an infected person’s respiratory tract when they talk, cough or sneeze. It can also spread by touching contaminated surfaces (such as a used tissue or door handle) or people's hands, and then touching your eyes or nose.

    • What makes flu particularly challenging is that you can infect someone the day before your own symptoms develop, and up to five days after your symptoms appear. That means you could give the flu to someone else before you even know you are ill.


    Flu usually makes people much more ill than a cold does. Flu symptoms usually appear 1 to 3 after exposure.

    • Sudden fever (usually 39ºC or above)
    • Dry cough
    • Achy muscles
    • Headache
    • Sore throat
    • Extreme tiredness
    • Runny or blocked nose and sneezing
    • Stomach symptoms, such as nausea, vomiting and diarrhoea (more common in children).

    Duration: Most people start to feel better within a couple of weeks, but for some people, flu can sometimes lead to life-threatening complications.

    Potential Flu Complications: Most people make a full recovery, but some people develop complications, which can sometimes be life-threatening. Complications may include:

    • Pneumonia (due to the influenza virus or a secondary bacterial infection)
    • Bronchitis
    • Sinus Infection (sinusitis)
    • Ear infection (otitis media)
    • Tonsillitis
    • Meningitis
    • Encephalitis

    And if you have a chronic illness -- like asthma -- flu can make your existing symptoms worse.

    Colds or Flu: When Symptoms Seem the Same

    It is easy to confuse a cold with the flu. Both are respiratory illnesses, and because some of the symptoms are the same - like a runny nose and a sore throat -- it can be difficult to tell them apart.

    Generally, flu symptoms are much worse than cold symptoms... and are more likely to affect your whole body, rather than just your nose and throat.

    • With the flu, you are more likely to have a fever, headache, muscle aches, extreme tiredness and a dry cough. Flu is also more likely to result in serious complications.
    • Cold symptoms are usually mild. With a cold, your main symptom is likely to be nasal congestion or a runny nose.