Depends on how many people in the area travel to other regions doesn't It?Also helps when you have an authoritarian government (one of the only benefits of such) that can effectively seal off the region.
Yes, it does and although authoritarian regimes can effectively seal off a region they can also do loads of other things like control information, conceal or invent statistics and basically make it appear that even quite outrageous things occuring on a massive scale do not present as such to anyone outside a region or the country. More importantly there are also consequences for going against / appearing to go against the regime, so there is less chance people will openly report problems and then keep reporting them if they aren't believed (as happened to the medics over there who got pinched for saying what was happening, or as happened to Weiwei for trying to find out the number of kids killed when their schools collapsed in that earthquake).
So the only thing we are left with is comparing their figures to elsewhere.
That disease had community transmission over there for at least a month and possibly a good deal longer than that, in a populous city and region and where there was a lot of travel (the New Year holiday). It isn't a country that can effectively seal itself off (like NZ or ironically enough Taiwan), and from their own reports we can see what measures were put in place to try and cope. We should also remember that there was no test for this for almost all of the worst parts of their outbreak, and no confirmed treatments either. The idea that they had 4000 dead, which would suggest <400000 cases based on the around 1% fatality rate that the rest of the world has seen, is clearly extremely questionable at best and at worst an outright fabrication.
Of course, we could find out the truth if independent experts went in there from the WHO with the freedom to find out the truth for themselves. That - still - hasn't happened.
