As has been stated in other answers, the N95 mask or respirator as it is often referred to is the best prevention as this is a respiratory illness. The surgical mask is different. The surgical mask will NOT provide protection as they have been designed to be more comfortable and they are not form fitted. They have leakage around the mask. Again, you need the N95 masks which is form fitted and has a metal nosepiece that conforms to the bridge of your nose. The 95 means that the mask or respirator is certified to filter 95 percent of particulate matter. You can get the superior N95 mask with elastic straps along with tips to avoid the swine flu at
http://www.silver-x.com