Australia did ban this years flu shot (which we are now using) for the under 5's after a couple of toddler deaths and numerous under 5 hospitalizations. However, the most compelling evidence would be the Cochrane Review - an independent organization that reviews studies. They concluded that the studies on flu efficacy were 'optimistic' at best and included serious flaws. The most damning evidence was that for children under 2, the flu shot had no more than a placebo effect. Yet still, the CDC recommends it for 6 months and up. Go figure!