Just moaned at my dad because we have been ill with flu for 10 miserable days now and he sent me an email saying it was basically because we live in London (wet weather, lots of people). This seems to have been confirmed by the fact that when we were recently on a rural Cornish holiday we were all very well and got sick as soon as we returned to the Big Smoke.
All you people who have moved from urban to rural - have you noticed that your children get sick less?