Cildhood ailments boomerang

Both I and my wife are down with a terrible cold for the third time this year - thanks to our 4 year old son who lovingly incubates the ailment and then passes it on to us at no extra charge.

Is this something that we have to accept as the normal course of parenting or is there a way to avoid it - like, say, confining him to bed at all costs.

I guess I know the answer here but given just how awful I feel this morning I thought I would trawl the net for some wisdom.