The Flare (virus VC321xb47) is a man-made disease. It is a virus that slowly eats away at the brain, and eventually turns victims into blood-thirsty insane humans. People who get the Flare are also called Cranks. The public are led to believe that it was freed from containment by the Sun Flares, but that is not the truth. It was once rumored that the sun flares caused a military container to burst, releasing the Flare. However, it is revealed in The Death Cure 's exclusive files, and in The Kill Order, that the governments of the world created and released it as a population control method. This is due to the need to control the general populace during the turbulent times of the sun flares, as well as to cut population, due to the destruction of food resources by the sun flares.
A small percentage of the population was resistant to the Flare, and were labelled as Immunes. WICKED attempted to use the Immunes to find a cure by looking at how the brain of the Immunes reacted to certain situations, as well as the physical make-up of the brain of the Final Candidate. People immune to the Flare include Thomas, Minho, Brenda, Jorge, and less than 1% of the Earth's population.