The Krippin Virus (also known as KV for short) is a fictional disease in I am Legend (film and novel). It was originally created as a cure for cancer. Hundreds of test subjects were injected with the serum and all became infected. This virus can be airborne, possibly from the breath of the billions of infected across the world carrying the virus in water droplets. Of the 6 billion people on Earth at the time KV broke out, only 12 million were immune to the virus. Since KV does not cause the infected to die and reanimate, the infected should not be considered undead or living dead.