The group known as the Regressives refused to use radioseptics, along with other advanced technology, contributing to the other Enarans' perception that they were a hazard to public health. Jareth, when speaking to Korenna Mirell, had mentioned the Regressive's refusal to use these devices and expressed his surprise that they hadn't started a plague due to non-use. Neelix demonstrated the use of radioseptics to Chakotay in 2372. (VOY: "Remember")