tiba,
I've been on a Layover in Hongkong/Kowloon in the second half of March just a few days after the press reported it as some severe disease now known as SARS. When I arrived, hardly anyone was wearing face-masks, maybe 2-3 people I've seen while checked out at the Airport.
Walking around town it was almost the same thing, no face-masks, apart of some people held half-heartedly tissues in front their face.
I suppose no one was panicking then. I've took rather common sence measures, like not touching anything unnecessary avoiding crowds (not using sub-way, etc.) and washing hands frequently.
4 days after I left HK while on Layover somewhere else, one night I felt extemely cold while under 4 blankets and 30 C weather outside. Once I fell asleep, I slept for 14 hours woke up for 1 hr and slept another 12 hours.
After that I was fine, and had no symtoms since. I don't know whether it had something to do with SARS, or whether it was pure co-incidence....but I've never slept for 26 hours before......
bottom line.....if I'd have to go now to HK/SIN etc. I'd get that face-mask and wear it until this thing is under control.