Hand Sanitizer vs Virus?

Unless I'm mistaken, a hand sanitizer is an anti-bacterial. Flu and cold are viruses. Why would a hand-sanitizer work against the spread of these bugs? I have always been under the impression that alcohol does not kill any type of viruses.

So how does hand sanitizer help prevent getting the flu if it wont kill or get rid of it?
Will hand sanitizer kill the Swine flu (H1N1 Virus)?

"Water was the most effective at removing stomach bug viruses from the hands, Emory University researchers find. They planted stomach bug viruses on volunteers' fingers and allowed them to dry. The results, presented this week at the American Society for Microbiology Meeting in Orlando, Fla., showed the percentage of the viruses removed by water, hand soap, and alcohol-based hand sanitizer. Water removed 96 percent of the virus; liquid antibacterial soap removed 88 percent; and the hand sanitizer removed only 46 percent."

Hand Sanitizer Effectiveness

Function
1. Hand sanitizers contain alcohol, which kills bacteria and viruses on the hands and helps prevent the spread of diseases such as stomach and intestinal bugs.

Warning
2. Hand sanitizers that contain less than 60 percent alcohol are ineffective in killing microbes, according to a 2006 study published in the Emerging Infectious Diseases journal (see References).

Types
3. Hand sanitizers can contain several types of alcohol, including ethyl alcohol, isopropanol or ethanol. Check the label for the alcohol type and its concentration, which should range from 60 percent to 95 percent.

Use
4. Hand sanitizers work best on hands that are not visibly dirty. Wipe or wash away the grime, then apply the sanitizer. Use enough to wet your hands thoroughly and rub your hands together until they are dry.

Considerations
5. The Centers for Disease Control, in its health care worker guidelines, recommends using a generous amount of hand sanitizer. If your hands are dry within 20 seconds, you have not used enough.