The whole CDC visit was not, as I recall, in the comic book, though I think it was a worthwhile addition to fill in viewers on the state of the world. The big thing that is lacking here, and seems to be left out of most of these zombie apocalypse stories, is the middle-story of what happened as things went from intial outbreak to final societal collapse. This episode at least gives a glimpse into that period. "World War Z" will cover that in more depth, if it ever makes it to the big screen; however, it would have made an awesome mini-series as well.
I frankly find it hard to imagine that larger pockets of society here in America and elsewhere would not somehow manage to quarantine themselves and survive, if this virus was only passed along by being bitten by an infected. Now, Dr. Jenner (the CDC guy in the last episode) mentions in his video log that the virus went suddenly and unnexpectedly global, which indicates there's something more nefarious at work. Later, we find out...SPOILER...
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Later, we find out that ANYONE who dies, even if they weren't bitten or otherwise directly infected, reanimate (i.e. come back as a zombie). This could indicate that the entire world may in fact have been exposed to something, near simultaneously, that caused corpses to reanimate spontaneously. Being bitten merely hastens the process by causing death sooner, rather than simply waiting for natural or accidental death. Given that many thousands of people around the world die each day through natural causes, accidents, crime, and war, it's no wonder the world's population was turned so quickly. This is especially true, given that the population would not initially understand what's going on, the how or why of it. Still, with 80 million Americans possessing fire arms, and a significant military capability, I would still expect pockets of resistence to remain. Nothing agains the French, but they're not the ones I'd expect to be the last to fall in this scenario (reference again to the season finaly of The Walking Dead). The Swiss or the Israelis I would think would be more likely candidates for "last man standing".
