2012 The Undead

The date of 12/21/12 is derived from the end of a 5,125 year cycle for the Mesoamerican Long Count calendar, most notably used by the Maya civilization. The calendar completes its 13th cycle from its starting point. Correlating the Mayan date to our Gregorian calendar yields several different dates ranging from the 21st through the 23rd, but the 21st seems likely, as it coincides with the winter solstice, and though astrology has little to do with our daily affairs, astronomically the Earth is said to be aligned facing the center of the Milky Way behind the Sun on the 21st. This interesting termination of the calendar in our lifetimes makes many people believe that the date will bring about great global change.
Current scientific research into disease, reanimation and cellular re-genesis is progressing as rapidly as other scientific disciplines. Particularly terrifying is the reanimation of the 1918 Spanish influenza virus, responsible for a pandemic that killed an estimated 20 million people. Scientists have gathered important new clues to why the virus spread quickly and killed efficiently. And the virus is being harvested from corpses, notably the body of a women buried in Alaska.
Diseases may break out that cause zombie like qualities. Weakened immune systems will make humans more susceptible to the likes diseases such as Trypanosoma brucei, a parasite that carries nightmarish qualities, reducing many of its victims to a zombie like state before they slip into a coma and die. Toxoplasma gondii can alter brain functions in rats, leading them to the jaws of cats – and in humans can change brain patterns to induce neuroses, paranoia and schizophrenia. Left with a rotting brain and primitive instincts, an entire population can be reduced to weakened stumbling shadows of humans, looking for food. Even though these people are not undead, their bodies are a heap of rotting, infectious and highly contagious flesh.
However, the threat of the actual invasion of brain dead zombies is a real possibility. Restoring a human from a cryogenic stasis and reanimating their dying brain tissue creates the possibility that a human may not be the same as they were when they died. This leaves a lot of speculation to a reanimated form of a human being.