Colds are very common and can be caused by about 200 viruses. Influenza is more serious. It is caused by a virus. It’s not normally dangerous if you’re healthy, but sometimes different strains of influenza can cause serious illness in some people.

If you get influenza, you need to rest at home and avoid infecting others.

What is influenza A?

Influenza A is caused by infection with a virus. It is often called the flu.

There are three types of influenza virus: A, B and C. Influenza A is more serious than B and C. It is the only type known to cause widespread outbreaks.

The influenza virus is always changing and evolving. In Australia, a new strain comes out each winter.

As well as infecting people, influenza A virus can infect animals, including birds (causing avian flu) and pigs (causing swine flu, H1N1). In some cases, these types of influenza can be passed on to humans.

Influenza A symptoms

If you have influenza, you will have some or all of these symptoms:

• fever and chills
• headache and muscle aches
• feeling tired and weak
• sneezing, and stuffy or runny nose
• sore throat and cough

Children may also have abdominal pain, nausea and vomiting.

It's a bit like a very bad cold, but a cold doesn't usually give you aches and pains.

If your symptoms get worse instead of better, it's best to see a doctor. You should also get help straight away if you feel chest pain, short of breath, dizzy or confused, or you are vomiting a lot.

Influenza A treatment

If you have influenza, you are likely to get better within a week or so by:

• resting in bed
• taking mild pain killers to relieve your pain
• drinking plenty of liquids
• eating light foods, when you're hungry

In some people, the flu can be severe and lead to serious complications like pneumonia. This is mostly likely to affect the very young, the elderly, pregnant women, Indigenous people, and people with chronic health problems.

If this sounds like you, your doctor might give you antiviral treatment to reduce your symptoms and prevent complications.

Preventing influenza A

Influenza spreads very easily from one person to another. If you have influenza, you should stay at home while you're sick, cover your face when you sneeze or cough, and regularly wash your hands.

If you are around someone with influenza, you can help avoid getting sick by regularly wiping surfaces they touch (use a cleaning cloth with detergent) and washing your hands.

It may help to get a yearly vaccination against influenza, before winter. The vaccine is particularly recommended if you are at risk of complications of influenza, or if you live or work with people at high risk of getting the flu.