I heard a bit of irresponsible journalism on the radio today. A reporter stated that people should wash their hands regularly to prevent infection/transmission of swine flu, but that masks were useless.
Now I agree that hand washing is probably MORE important than wearing a mask, but a mask can still help! I'm specifically concerned that someone who thinks that they are infected with swine flu may decide to fore go a mask because they think it doesn't make a difference. If you are infected, wearing a mask is of utmost importance if you are going out in public, which you hopefully aren't, because a proper mask will prevent the transmission of your germs to everyone around you.
If you aren't infected, wearing a mask can help stop germs from getting into your body, but unless you are in an environment where you are in close proximity to infected individuals (like you work in a hospital) you probably are at a lower risk of infection. Most infectious agents do not remain in the air for long after they are expelled by their host (i.e. after a person sneezes). Of course if you want to play it safe, why not put the mask on. Better yet, get the mask companies to make designer masks that make you look like a superhero.