Vitamin E acetate was an early suspect as a cause of vaping-related illnesses after scientists in a NY lab discovered its presence in many samples of products used by sickened vapers.
However, one previous study found no evidence of the lungs being coated by oil in tissue samples taken from 17 EVALI patients across the U.S. Rather, the authors concluded in their study, published in The New England Journal of Medicine, that the injuries are similar to "chemical pneumonitis", or inflammation in the lungs caused by breathing in chemical fumes. The latest findings point to growing evidence of vitamin E acetate as "a very strong culprit of concern", she said.
The findings are significant because for the first time, scientists have been able to connect results from product testing with clinical specimens from patients, she said.
It isn't clear how widespread the use of vitamin E acetate is in e-cigarette and vaping products.
Most of the patients who have fallen ill or died from vaping had used THC in some form - though as the Washington Post notes, in at least three cases, THC was found in the systems of patients who said they had not vaped or consumed any pot. The bulk of the cases occurred in August and September but new cases are still being reported.
Vitamin E acetate is believed to be used as a cutting agent in illicit products containing THC - the component of marijuana that gets people high.
Vitamin E acetate is found in lots of foods and is used in supplements and skin creams. The CDC said the lack of THC in five of those samples does not definitively indicate the patients didn't use the drug, because THC can be hard to detect in samples taken from lungs.More news: Sharma blitz flattens Bangladesh as India draw level
More news: Indian duo arrested for spot-fixing
More news: Merkel slams Macron for calling North Atlantic Treaty Organisation 'brain dead'
E-cigarettes and other vaping devices heat a liquid into an inhalable vapor. The investigation has found that many of these products patients used were bought online or received through friends or family, rather than through vaping shops or at licensed THC dispensaries.
Symptoms of the vaping illness include trouble breathing, chest pain, fatigue and vomiting.
Anne Schuchat, the CDC's principal deputy director, said tests have been conducted for a wide variety of substances, including plant oils and petroleum distillates. The vitamin E discovery "does not rule out other possible ingredients", Schuchat said.
The CDC has issued numerous warnings since the outbreak began, including advising people not to vape any products that contain THC.
It was an exhaustive list of more than 1,000, said Pirkle, who oversees agency's chemical analysis labs. "THC is not something we would expect to be hanging around in the lung fluids", whereas vitamin E acetate is "enormously sticky... like honey", he added.
"We really need the animal study to nail down cause and effect", he said.