A few years ago Hong Kong was experiencing an epidemic of avian flu, with a number of folks dying from it. We had a trip that stopped there with about a 48 hour layover, then went to Subic Bay, then up into China, and then back to Hong Kong for another reasonably long layover. The company gave us a few masks to wear, you know the kind that a painter or someone doing some light sanding might use, the kind with the two elastic bands that hold the mask to your face. It wasn't very comfortable to wear and by the time we had left the main terminal, we both had already removed them. Lots of folks walking around downtown were wearing masks, but not us. On the positive side, when we went to dinner, there were no crowds, and all we needed to do to have the place all to ourselves, was to cough loudly. That really cleared the place out in no time.