Sharon Levy, director of the adolescent substance use and addiction programme at the children’s hospital in Boston, Massachusetts, is quick to recall the first time a teenager with vaping-induced nicotine poisoning arrived at her clinic.

“This was about a year and a half ago,” she says. “I remember sitting, talking with him about his experiences using [the e-cigarette] Juul, and it became quite clear to me that the symptoms he had were basically nicotine toxicity. Nicotine is sometimes used as a pesticide in very high levels, [...]