Immunity Challenge is an Extreme Contest where challengers proceed to expose themselves to various pathogenic agents in an attempt to stress their immune system to the verge of collapse until only one contestant remains standing. While Immunity Challenge was initially designed for participation by tweaks and near-baseline humans, the game rules can be easily modified to be played by any sapient being regardless of phyle. After each round the remaining contestants are exposed to either higher doses and/or increased diversity of pathogenic agents. For biont competitors events commonly include exposure to one or multiple categories of virus, fungi, bacteria, archeae, nanite, prion, protozoa, and malignant neoplasm.
The Interpolity Association of Immunity Challenge (IAIC) was the sport governing body that was originally tasked with regulating the sport. IAIC ensured sentient rights for both the participants and the artificial immune system, where applicable, were enforced and that no inexcusable manipulation or coercion was involved. In most major polities in the Terragen Sphere participation required proof of recent backup/copy and legal waiver was standard on most civilized worlds. However, amongst barbarians and throughout The Wilds, where the reach of IAIC to carry out disciplinary action for rule infractions was limited, Immunity Challenges would occur without safety nets. Restoration should a contestant lose the contest would not be an option in this later case.
Some rule variations of Immunity Challenge require the disabling of Genematode, Technocyte, and other similar artificial augmentation of an immune system. While a few of the more virulent pathogens are capable of simply overwhelming artificial immune system to render them inert, most often contestants will agree or rules will stipulate ahead of time to deactivate portion or all of immune system. Shutting down normally utilizes the designed inbuilt safeguards and fail-safes mechanisms of artificial immune system for host microbiome alterations and genome updates. While multiple methods are available for both permanent and temporary disabling parts of the natural and artificial immune system of contestants, nearly all are reversible to an extent and can be restored after competition is over. Having a strong residual immune system is not enough to guarantee victory, since rounds can be deliberately constructed to induce immune system dysfunctions like hypersensitivity, cytokine storm, and autoimmune disease.
The time for an average challenge can take anywhere from microseconds for certain vir simulated infections upwards to decades for certain prions and malignant neoplasm to run their course. The length of a challenge is determined by the category of pathogenic agent and the virulence of the pathogen being used. Even with the most virulent diseases there will be a clear delay between start of an event and onset of symptoms so several strategies are employed to keep audiences engrossed. Immunity Challenge events are extensively edited temporally by the media. Broadcasting multiple rounds simultaneously, cropping down to highlights of events, and time-lapse recording to condense events into manageable parcel are all commonly employed by those covering Immunity Challenges. Immunity Challenges also make use of neural interface connections between fans and players to increase enthusiasm amongst their audience. Fans can feel what contestants are experiencing both in real time and replay past challenges through simulation archives.
Immunity Challenges can trace their roots back to the diagnostic regiments used by biomedical megacorporations during the Interplanetary Age to observe the in situ response of immune system in new tweak genemods. A concurrent contributing source to Immunity Challenges was the internal tests put in place by early AI and software developers that simulated malicious attacks to probe the durability firewall and security measures in place. The first public event that could be considered an Immunity Challenge would be the 2190 Genetic & Biological Augmentation Exposition where tweaks representing the latest genemod from Biowulf Pharmaceuticals and IntraGenic faced off in a head to head match in order to demonstrate who had the superior product. Contemporary pundits describe the event as "getting out of hand", and having to be stopped before an official winner could be declared when all participants were hospitalized suffering from various degrees of necrotizing fasciitis.
The sport gained fame early in the Interstellar Era when Abraham Rhee successfully survived a combined exposure of Retroviral Typhoids and blue goo 4.2 of New Timbuktu. After an outbreak of a highly virulent strain of Marburg Virus on the long running series Beta-zed-null-xi hosts Hu's do the Dumbest Things, many polities stepped in and began to increasingly regulate the sport and competitions stopped being held in front of live viewing audiences.
Popularity started to decline in The Age of Crisis, with the disintegration of IAIC starting in 7055 into regional governing bodies due to widespread allegation of immune system tampering by professional contestants and poor advertisement revenues. By the 9th millennium competitions with stronger memesets had relegated Immunity Challenges to the periphery of sports, performed mostly by reenactment groups and backwater communities. While Immunity Challenge had slowly disappeared from real life, it continues to be played in numerous virches spread through out the Terragen Sphere.
In the past two centuries a drinking game version of Immunity Challenges has become popular in both the Zoeific Biopolity and Utopia Sphere. The copious consumption of alcohol after each round and increasing sleep deprivation helps to suppress the immune system of contenders and bring about a decisive win quickly.