Boren Syndrome

Boren's Syndrome is a condition that Sergeant Avery Johnson has, caused by exposure to high yield plasma grenades. It was contracted when he used an entire crate of plasma grenades to hold off Covenant forces on Paris IV.

Symptoms
It has several symptoms including brain tumors, migraines, and amnesia. Without proper treatment, it may also cause death. But because of this condition, the sergeant's neural pathways are changed in ways that do not allow the Infection Form to match its mental frequency. The sergeant has not recieved treatment for the syndrome (30 weeks of chemotherapy), and therefore should die soon.