I was just telling this to a friend who was panicking today. Knowing the communist mantra of "If I don't report it then it's not my fault" and seeing how shitty chinese healthcare seems to be, I'm sure this had chances to spread around in china probably at the very least since December, then it also probably took some time until the appropriate places finally admitted to themselves that something was odd and entered the proper channels. If it was very infectious I would assume that there would be clusters of this disease popping up all over the western world, especially with the hyper-sensibility to reporting people have to it now, but it doesn't seem to happen quite and almost all examples of it in the western world they seem to be able to trace back directly to China quite easily, instead of having complicated infection chains. If shit doesn't go down suddenly the next week in western countries, I don't think it's going to be on the scale of China in the west. I don't think people quite understand how interconnected the world these days is and how many people move from country to country every single day. If it's very infectious and robust against sanitary measures, it's everywhere at this point.
Then there's also the theory that asians might be intrinsically more vulnerable which is of course way too early to claim but I wouldn't outright reject it either at this point.
I really wonder if this will be Chinas Chernobyl.