It also does not survive very well outdoors. I think the problem with lab created anything is that translating it to the real world is always a step assumed by people in the lab more than something they themselves run out to do. I guess it is a good thing that bioweapons created in a lab might not be so effective in the real world, and there haven't been real lunatics testing them on populations openly. I read somewhere how there is a trade off in doing these experiments on virus that spread easily in that they tend to be more like minor inconveniences than deadly monsters, and that they tend to quickly evolve less deadly over time. They want something that will spread quickly and kill quickly-- they themselves are the virus they have been searching for all along.