In the book, North Korea was completely destroyed early on. No one knew exactly how, but the border guards one by one stopped coming to the border, and then suddenly it was quiet. Survivors speculated that they evacuated to their underground bunkers, along with some infected, and were all zombified underground.
Israel's survival wasn't political, it was simply that an intelligence operative figured out early on that there was a fast spreading disease, and so they allowed Jews and Palestinians who had lived in Israel the chance to come back, sealed themselves off, and survived.
The most political was Cuba. It thrived after the apocalypse. All over the world people fled in boats to the ocean to get away from the zombies. Americans fled in boats to Cuba. They were kept in prison camps, and did slave labor for a few years, but eventually the government had to let them out, and so they blended into Cuban society. This caused the citizenry to rebel against the communists, and the government had to relent and give the people their freedoms back.
The book was awesome. Movie should have been directed by Ken Burns as a pseudo-documentary.
I read about 1/3 of the book and returned it to the library. Very tedious. Could not finish it.