[umilegenio]

I am not sure how much matters, but Italy has a high population density, higher than China: 201/km2. China has 145/km2, while United States has 36/km2. This mean that people are more widespread, so it should be easier to isolate parts of United States than it is to isolate parts of Italy, in case there are problematic areas. In short, New York might become a center of epidemic, but probably not the whole United States.

[magicsmoke]

China's population density is skewed lower due to uninhabitable and sparsely inhabited mountains and deserts in Xinjiang and Tibet that make up about half the country. Without those regions China's population density doubles to around 300/km2.

[umilegenio]

True, mine is a generalization. However Italian geography also lead to heavy concentration of people in limited areas. Lombardy, the worst hit region, has a population density of 420/km2. Look at this map of Italian geography: https://en.wikipedia.org/wiki/Italy#/media/File:Italy_topogr...

[Jommi]

Is there a country where this is not the case?

[Zenst]

That's an issue as many live in pockets and those pockets are dense in populus. So population density needs to be looked at on a city/town basis as counting all those deserts and farming land etc, to dilute the numbers can skew perspective.