I wrote before about the ineffectiveness of hand sanitizers. Slate has a new article reiterating in more detail why relying on hand sanitizers is not an effective way to fight off the flue, or H1N1.
Without getting into a lengthy post, I'll summarize. If you want to prevent illnesses, wash your hands after using the restroom, before cooking, before eating, or any other sensitive situation as such. If you have a need to ensure your hands are clean, wash for twenty seconds with soap and warm water. Don't use hand sanitizers, wipes, or any other such cleansers unless it is absolutely the only thing you have available.
Lastly, eat the right foods and keep a positive attitude.