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What causes colds and flu?

2-minute read

Colds and flu (influenza) are very contagious viral infections and you can catch a cold or flu at any time of the year, not just in winter. However they are more common during the winter months, possibly because people are more likely to stay indoors and be in close contact with each other.

If you have a cold or flu and you sneeze or cough, tiny droplets of fluid containing the virus are launched into the air. These droplets spread about 1 metre and are suspended in the air for a while where they can be breathed in by someone else who may then become infected.

These tiny droplets of fluid can also land on surfaces. Anyone who touches these surfaces can also catch a cold or flu if they pick up the virus on their hands and then touch their nose or mouth.

If you have a cold or flu and you touch your mouth or nose and then touch a person or object without first washing your hands, then you can also transfer the virus to that person or object. Good hygiene is one of the most important ways to help prevent colds and flu (influenza).

Everyday items at home and in public places can easily become contaminated with traces of these viruses including food, door handles, remote controls, handrails, telephone handsets and computer keyboards.

Not sure what to do next?

If you are still concerned about your cold or flu, why not use healthdirect's online Symptom Checker to get advice on when to seek medical attention.

The Symptom Checker guides you to the next appropriate healthcare steps, whether it's self care, talking to a health professional, going to a hospital or calling triple zero (000).

Sources:

NPS MedicineWise (Respiratory tract infections (RTIs) - nose, throat and lungs), SA Health (Flu (seasonal) - including symptoms, treatment and prevention)

Last reviewed: May 2018

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