Numerous products used by those who became ill were illicitly obtained, public health experts have said, by patients who bought them from friends or on the street.
USA health officials have been sounding the alarm amid a nationwide outbreak of serous lung illnesses linked to vaping, and have raised concerns about the use of electronic smoking devices, particularly among youth.
As of Tuesday, there had been 2,051 confirmed and probable lung injury cases associated with e-cigarettes or vaping products in 49 states, the District of Columbia and the Virgin Islands, the Centers for Disease Control and Prevention reported, with 39 of the cases fatal.
Vitamin E acetate is a thick and gummy syrup, similar in consistency to honey, that some illegal makers of vaping liquids use to dilute their product in order to reduce the amount of active ingredients they need to add.
Scientists may finally know what's behind vaping lung illnesses that have sickened more than 2,000 in the United States: a combination THC and an oil derived from vitamin E, the Centers for Disease Control and Prevention (CDC) said Friday. Vitamin E acetate "could potentially be used in a variety of substances", Schuchat said.
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As the New York Times reports, the CDC says the finding is based on samples taken from the lungs of 29 of those sickened from vape use.
"These findings provide direct evidence of vitamin E acetate at the primary site of injury" in the lungs, Dr. Anne Schuchat, the principal deputy director of the CDC, said during a news conference today (Nov. 8).
While vitamin E is safe as a vitamin pill or to use on the skin, inhaling oily droplets of it can be harmful. But none of them were found in the lung fluid samples.
The agency collected lung fluid samples of patients with EVALI, short for "E-cigarettes or Vaping product use Associated Lung Injury", as part of its ongoing investigation. Nicotine was detected in 16 of 26 patients.
But the investigation moved away from the acetate as it became clear that the vast majority - 82 percent - of illness-linked samples contained THC, the psychoactive ingredient in cannabis. The CDC also tested the samples for other chemicals commonly found or added to THC products, like mineral oil, terpenes and more, but none were detected in the samples. Health investigators have said since almost the beginning of the outbreak in mid-August that some ingredients, including vitamin E acetate, could be responsible for some of the lung illness cases. A subset of 66 people who suffered lung damage indicated they were nine times more likely to have used illicit products and to have indulged more often. It usually does not cause harm when swallowed, but its effects when inhaled have not been extensively studied.