There are several things that make this disease quite different from, say, an outbreak of the plague or yellow fever.
First, the carriers are already contagious
before they even show symptoms. This alone makes containment almost impossible (nevermind the extreme virulence and contagiousness, the absurd number of different vectors, or the fact that some of these vectors
can fly). Combined with the speed it spread at, this makes unlikely for most governments to even realise something serious is going on before they even have time to take appropriate measures — and nothing short of a complete lock down of the country and a scorched earth policy on all the borders with a neighbouring country, very soon, will help — which most government aren't even
willing to do.
Second, between the outbreak of the disease an the appearance of monsters, there is another dramatic thing that happens: the collapse of society on a worldwide scale. Because the disease affects a very high number of people in virtually every country it enters (and it enters almost every country), and because the survivors are for a large part people who flew into safer areas, that means you get a refugee situation on a global scale, with no one able to provide helps (since the rare spared countries are on lock down). The production chains collapse very quickly, people soon run out of electricity, gas, food, clean water and drugs; famine, cold and epidemics would take a very harsh toll to the survivors, even if there were originally 2 billion of them — not to mention inevitable armed conflicts over the rapidly vanishing vital ressources.
This, of course, is a gradual process that takes months and years; the situation eventually stabilise around the few pockets of civilisation that have managed to organize in a sustainable manner; but as these groups then try to reclaim the cities, they find out that they can't because there is something even worse than the disease: the cities are now occupied by dangerous monsters
that are still contagious. But by the time we have managed to overcome immediate survival problems and truly become aware of the monster infestation, several years have passed and less than 1% of humanity is still around, in isolated enclaves living around the globe in cold, harsh and difficult-to-acess places.
Even for the few countries that have managed to avoid contamination, like Iceland, they still find themselves suddenly completely isolated. All the ressources they imported are gone. All foreign trade and foreign aid is gone. That likely means running out of many kind of food, running out of oil and natural gaz, running out of various metals and other material useful for chemistry (you want to make a lighter? sorry, no oil; matches? sorry, no sulfur, no phosphorus), running out of specialised medications made in foreign laboratories, and so on.
So in short, that's not to say nobody in America would survive, but to imagine that America could come out of this entirely unscathed doesn't seem very realistic.
Poll
