We're a family against the flu vaccination.
Our child is 4.5 and has been going to playgroups since he was 1. We've had no major dramas nor any regular onset of the flu. He does take Vit C capsules, gets lots of sleep and runs in the sun (at least 10 minutes a day) for his Vit D. And, he gets lots of exercise and lots of fruits and vegetables in his diet too. His doctor says that his immune system is pretty darn good as even when he caught HFMD, he had a mild reaction. In general, he is quick to recover from any flu/cold he gets.
We have a newborn and when I was down with the flu (last week), she showed no signs of it either. Her immune system seems to be fine and when her brother had HFMD, she didn't catch it either. So we'll be going down that same road - No flu vaccinations.
We made an informed decision (looked at the ingredients and didn't like it, read up on side effects and also, my own personal reaction to the flu vaccination) and decided that it's best for our children to build their own immune system. We do not leave it to chance as we do ensure that their diet and lifestyle are healthy with lots of Vit D and Vit C!
Good Luck with your decision!