I, like BBBevan, was a teacher and caught something from the little darlings at the start of every term: the Autumn cold/flu, the Spring chill and the Summer bug. I have had the odd cold since I retired but not so many and, due to decreased stress levels and not having to work while ill, not so serious.
I think there are several precautions you can take to prevent colds, chills and flu. Cold are a rhinovirus and develop in the back of your nose. Keep your nose warm with a scarf (also prevents germs entering) and use one of the 'Stop-a-Cold' remedies if you feel a tickle. They are expensive, £7/£8 or so, but worth it to save yourself froma week's misery.
Clean door handles, wash hands and launder towels frequently. Avoid others with sniffs and chills and, if you see anyone sneezing, walk the other way quickly as the germs explode quite a distance.
Being conscious of where the viruses come from and how they are transmitted will convey a level of awareness which will keep germs at bay.
If you do catch a cold -and no one in this country could avoid this entirely - then use the 'Stop-a-Cold remedy as directed on the box as they also shorten the life of the illness by about a day.