So masks *do* work...

An earlier post expressed skepticism about how effectively masks prevent transmission of flu. Now a clinical trial has shown they can prevent transmission of disease from others to the wearer:

Worried about the flu? Get a mask: Scientific American Blog:

"All of the participants were initially healthy but at risk for catching viruses from their children, who had documented cases of respiratory illness. The researchers found that, after a week, the non-mask wearers were four times more likely to catch a variety of viruses, including the common cold and flu, than those who wore them properly (meaning they strapped them on whenever they happened to be in the same room as their sick children). The masks appeared to be equally effective."

If I'm reading correctly, plain old surgical masks were just as effective at preventing transmission as the more expensive P2 masks, which are "specially designed to filter out water droplets containing viruses".