|Homeworld||None (Rumored to be spread by radiation poisoning by Covenant weaponry, not microorganisms)|
*Minor genetic mutation
*Possible immunity to Flood infection
Boren's Syndrome is a non-existent disease falsely-stated to infect humans as a cover-up story for when ONI was working to hide the identity of children kidnapped for utilization in the Spartan program as Spartan-Is.
In The Public Eye Edit
ONI (the Office of Naval Intelligence) spread the story about the non-existent disease to the public, and included with its description a number of equally-non-existent symptoms to appear that it was like any other illness. Descriptions of such symptoms may suggest it was caused by radiation poisoning, and thereby included tumors, migraines, et cetera. There were unconfirmed claims as to the initial cause of the disease's outbreak, including claims that it started with the inhalation of gases released when Type-51 Carbine magazines were ejected to being exposed to Plasma Grenade radiation (both being Covenant weapon, which secondarily would aid in an even greater racial hatred towards the Covenant which would likely lead to even more recruits for the United Nations Space Command).
Several members of the United Rebel Front also claimed to have this condition in hopes of bargaining with the UNSC in order to not only gain treatment for the condition pre-infection but also to trade it for FENRIS Nuclear Warheads that they had in their possession. Despite the fact that those of ONI likely knew this to be a false statement (assuming anyone from ONI even had gotten word of this trade-off), the United Rebel Front had in fact utilized the planned bargain as a trap set up by Howard Graves in an attempt to capture Spartan-IIs.
Staff Sergeant Avery Junior Johnson was assigned falsified medical records in order to disguise his real, classified record. This false record claimed him to be a sufferer of Boren's, having contracted the disease on Paris IV after coming into contact with dangerously high amounts of radiation apparently originating from a crate of captured Plasma Grenades. This false record (known in ONI as the Paris/BS Spoof) was most likely a successful attempt to avoid any investigation into his altered DNA (as radiation is known to work as a form of genetic mutagen).
Fake Long Term Effects Edit
It was stated that if Boren's Syndrome cases were left untreated or unsuccessfully treated in some way, it could become fatal or at least debilitating to the host. While some effects such as migraines could certainly be managed with medication, the tumors that were said to be involved in the disease usually - or possibly even always - became malignant. As such, treating Boren's Syndrome invariably meant treating cancer, a process that can be debilitating to the individual. The only known cure for BS was an intensive regimen of chemotherapy that lasted for thirty weeks.
According to this theory, some combination of the disease's apparently multitude of pathologies discouraged Flood Super Cells, which would explain why Sergeant Johnson was incapable of being infected by the species when he and his squadron were ambushed by the Flood on Installation 04, which led Master Chief Petty Officer Spartan-117 to his ultimate moral dilemma. An ONI scientist, Dr. Catherine Halsey also was quoted as guessing that there would be a billion to one chance that Johnson's condition could be reproduced.
Even so, there is technically no explicit proof that Boren's Syndrome discourages Flood in any manner; instead it may be that the nervous system of a Boren's Syndrome carrier simply cannot support Flood. One hypothesis is that an infection form attempting to latch on to a host with Boren's Syndrome would recognize the characteristic neurological disturbances as "irreparable damage," thus rendering the sufferer immune to their parasitic behavior as such (although certainly not immune to them subsequently killing the "unhostable"). However, it is highly likely that if this condition did in fact prevent Flood infection the Forerunners would have discovered it after hundreds of years of research into Flood prevention.