Some 77% of people with so-called vaping illness used black-market products containing the cannabinoid THC, the CDC said Friday, based on interviews with 514 victims.
In a , CDC and state investigators were careful to note that no one type of vaping product was involved in all cases.
"However, the vast majority reported using illicit THC-containing products sold as prefilled cartridges and obtained from informal sources," they wrote.
As of Thursday, the 805 total cases of lung injury, including 12 deaths in 10 states, relating to vaping and e-cigarette product use.
Analysis of 373 cases for which complete sex and age data were available revealed that:
- 72% have occurred in males
- 67% occurred in young adults ages 18-34
- 38% were in people under age 21 and 16% were in people younger than 18
- 17% of cases involved adults age 35 years or older
Data provided by health departments in the 46 states and the U.S. Virgin Islands in which vaping illnesses have been identified revealed that most, but not all, patients reported a recent history of vaping products that contain the cannabinoid tetrahydrocannabinol (THC) or a combination of THC and nicotine.
In a telephone press briefing held Friday, Illinois Department of Health Chief Medical Officer Jennifer Layden, MD, PhD, said that while the investigation of cases in Illinois and Wisconsin identified no single brand or product associated with the illnesses, a "high percentage" of the cases interviewed reported using a THC vaping product marketed as Dank Vapes.
In a , Layden and colleagues noted that "Dank Vapes appears to be the most prominent in a class of largely counterfeit brands, with common packaging that is easily available online and that is used by distributors to market THC-containing cartridges with no obvious centralized production or distribution."
The investigators noted that it has not been determined whether the THC in the prefilled cartridges or some other substance, such as cutting agents or other adulterants, is causing the illnesses.
Indeed, CDC Principal Deputy Director Anne Schuchat, MD, confirmed Friday that no single substance has been identified as being associated with vaping illnesses.
"We do not know yet what exactly is making people sick," she said. "Whether particular solvents or adulterants are leading to lung injury, or whether cases stem from a single supplier or multiple ones."
She said based on the most recent reports the CDC recommends that people avoid using e-cigarettes or other vaping products, "particularly those containing THC."
Speaking Wednesday at a U.S. House of Representatives committee , Schuchat acknowledged that she was "extremely frustrated with the pace of our investigation."
"We have more than 100 people working on this and the states are also making this a top priority," she said. "I think the FDA and DEA doing product sourcing can help. But I actually think there may be a very complex set of root causes here that are going to be difficult for us to address as a nation."
Schuchat identified underground vaping supply chains "that are adulterating products in ways that are experimental" as a specific challenge to investigators.
FDA's acting commissioner, Ned Sharpless, MD, said the agency's analysis of vaping products linked to the illnesses covers many chemicals found in e-cigarette liquids including nicotine, THC and other cannabinoids, opioids, cutting agents, pesticides, and other toxins.
"Additionally we are working with Customs and Border Protection to identify illicit vaping products at international mail facilities," he said. "FDA's Office of Criminal Investigations is focused on identifying the products that are making people ill, and following the supply chain to the source."