Just a tiny amount of fentanyl, the equivalent of a few grains of sand, is enough to stop a person’s breathing. In 2023, he became the cofounder and CEO of ARMR Sciences to develop a vaccine against fentanyl. Now, the company is launching a trial to test its vaccine in people for the first time. Widespread distribution of the medication contributed to a 24 percent decline in US drug overdose deaths in 2024. Opioid vaccines were initially proposed in the 1970s, but after early attempts at heroin vaccines failed, much of the research was abandoned.