During the Yuuzhan Vong War, the Yuuzhan Vong empire conquered the planet Wayland where they learned of the presence of a stronghold that belonged to the late Emperor Palpatine. Conducting drilling operations, they discovered the chemical formula for bacta which the Shaper caste analyzed. This led to the creation of a plague weapon designed to target its effect and led to an initiative being conducted by the Shapers to target bacta production. The project was overseen by the Shaper Viith Yalu who intended to cripple the New Republic during the short cease fire at the time. To accomplish this goal, he made use of the mentally disturbed Jedi Bey Gandan as a carrier for the plague and smuggle it to Thyferra.
The agent was something akin to a virus that attacked the alazhi plant from which bacta was created. Rather than kill it, the virus worked on a more subtle basis by mimicking the active chemicals as well as bacteria in alazhi whereupon it goes quiescent. Thus, it became completely undetectable unless one knew where to look and stayed in this state until it was brewed with kavam to produce bacta. It was relatively harmless in this state until it was introduced into a living subject where it activated at a low level akin to a time bomb. after a few weeks of regular bacta treatments, the subject eventually dropped dead in a matter of hours. Once administered, there was no cure to the plague and no reversal of the process. After being infected, the alazhi plants passed on the virus genetically through spores that were self motivated and targeted the chemical signature of the alazhi plants. This led to a rapid infection rate meant it capable of tainting an entire world of its bacta within days and had the potential of killing millions due to the wide spread use of bacta.