The germs that cause flu are spread from someone who has the flu, or is coming down with it, via droplets that are sprayed out of the nose or mouth. A cough or sneeze can propel these germs up to a metre (or three feet) - it's no wonder that the flu virus spreads so quickly!
All you have to do is breathe in these liquid droplets from the air, or touch a surface or object that the virus has landed on and you may well have been contaminated too.
Food for thought:
The flu virus can live on hard surfaces (door handles, banisters etc for up to 24 hours and soft surfaces such as sofas and bedding) for around 20 minutes. When it comes to trying to avoid cold or flu germs there is a good case for handwashing.
Check out some other flu related articles!