Or Antarctica? Or Iceland? Maybe New Zealand, Australia, and Malaysia, but not the Pacific Islands. Madagascar, sure, but the Falklands? And this is ignoring oil rigs, research stations, and survivalist bunkers. It's simply unfeasible that humans would be wiped out by a plague that couldn't reach all of them. Moreover, zombies would be infected, which means that motor control and motor power would severely decrease, letting even your average baseball bat take out nearly all of them, if the tanks and machine guns didn't first.
When was the last time the World did not survive a disaster? We would always find a a way to survive, It's in our instinct to survive because if it's not, We will not exist, Our ancestor fought large predators during the Ancient era but they did survive. So yes!
Theoretically, if a weaponized, intelligent virus were to go airborne, then it could easily spread throughout the world, affecting at least three quarters of the population.
The possibility of a zombie apocalypse, however, is practically nonexistent. Neil Degrasse Tyson recently debunked the logic of zombies. I mean he blew zombies out of the water on multiple fronts. The biggest thing is that in order for zombies to have any type of function, they would have to have blood flowing to their brain to sustain activity.
Even if some type of virus could mutate into a zombie strain, the human race is very stubborn. Plus the number of firearms in America make it a likelihood that any survivors would be well equipped to defend against zombies.
Even though the possibility of an apocalypse is nearly nonexistent, I find it hard to believe that the most of the world would survive. If a virus were to go airborne, it could possibly infect half or more of the population. From the point of view from someone living in the U.S, I feel as if these poor, underfunded countries would be the first to go. There'd be no possible way that they, themselves, would be able to protect themselves from "zombies." There would be no sufficient shelters, food/water supply, or much of anything else that would even help them kill and save themselves from infection. Unless they devise a plan to creat weaponry and a sturdy shelter, which is highly unlikely (for the sturdiness of a shelter). Places like Africa, North Korea, etc. There are even places with climates that would be hard for survival, such as Antartica, Alaska, Hawaii, etc. Though the U.S, Canada, and some other places may be able to fund themselves and find sturdy shelters and sufficient supplies of food and water, other places may find it hard to survive. In conclusion, I feel that maybe some of the population may survive whilst more of the population may not.
Assuming the "zombie plague" is a virus, it seems unlikely that we would survive, with the exception of a few preppers. Because the RNA in viruses is unstable, they mutate very often. With natural selection and a high mutation rate, the virus could adapt fairly quickly. And even if the zombies themselves couldn't get to isolated places, the virus might be able to. It would likely adapt to be resistant to extreme temperatures, and possibly become airborne or waterborne. And, taking these factors, as well as a possible period before symptoms appear, into account, an infected person could get onto a plane while fleeing the virus and infect more people, spreading it to isolated places where people feel safe.