Colds are very common. Children may get 5-10 colds a year, while adults may get 2-4 colds each year.

Colds affect the nose, the throat and upper airways, and common symptoms include coughing, fever, sore throat, sneezing, blocked or runny nose and general congestion.

They are caused by about 200 different viruses and there is no vaccine for a cold.

The flu is a viral infection affecting your nose, throat and sometimes your lungs. Typical symptoms of flu include fever, sore throat, tiredness and muscle aches.

Symptoms of a cold tend to be mild to moderately severe.

Both colds and flu can also lead to complications, such as pneumonia, which can sometimes lead to death.

Three different types of influenza viruses infect humans - types A, B and C. Only influenza A and B cause major outbreaks and severe disease.

There is a vaccine available for the flu and it's recommended 'at risk' people, such as the elderly or those with chronic illnesses, have an annual flu vaccination. Flu viruses circulating in the community continually change, and immunity from the vaccine doesn't last a long time so that's why yearly vaccination is recommended.

Good hygiene is one of the most important ways to help prevent colds and flu.

Other ways to help prevent flu can include antiviral medicines, although these are only recommended for preventing flu if you have been exposed to the flu in the previous 48 hours.

Antibiotics only work for bacterial infections so they won't work for colds and flu which are caused by viruses.

If you are feeling concerned about any symptoms of a cold or flu then see your doctor. If you would like to speak to a registered nurse, call healthdirect on 1800 022 222, 24 hours a day, 7 days a week.

For more information on the flu vaccine, go to the Immunise Australia website or call the Program Information Line on 1800 671 811.

For more information about Australia's strategy to manage influenza pandemics go to www.health.gov.au.