Anne Schuchat, principal deputy director at the CDC, called it a "breakthrough" in their investigation.
"The CDC's reporting supports what New York State's Wadsworth Center Lab has found in vape products tested since early September and reinforces the importance of the role that Vitamin E acetate may play in the current outbreak of vaping related illnesses", New York Gov. Andrew Cuomo said in a statement on Friday.
In the CDC analysis, THC was detected in 23 of 28 patient samples of lung cells, including from three patients who said they did not use THC products.
Officials tested the samples for a variety of substances, including mineral oils, plant oils, diluent terpenes, cannabinoids, and nicotine, as well as a common component of lung secretions. But "in those that were tested so far, it's primarily been [in] THC-containing e-liquids".
Based on these data from 29 patients, it appears that vitamin E acetate is associated with EVALI; however, it is possible that more than one compound or ingredient could be a cause of lung injury, and evidence is not yet sufficient to rule out contribution of other toxicants to EVALI. 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.
Vitamin E is used in several products, such as lotions and in supplements, but the CDC said there is a "big difference" in putting vitamin E on the skin or swallowing it in pill and in inhaling the oily vitamin.
The Illinois survey of 4,600 people who vape found 94% of respondents reported vaping only nicotine while 21% vaped only THC and 11% said they vaped both. Vitamin E acetate has been highlighted as a huge concern by proponents of vaping for months, and once people began falling ill it seemed like the most likely culprit. "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.
Scientists theorized that the oil might be coating the lungs, triggering inflammation and damage.
The oil was found in all 29 samples, the Post reported.
She cautioned that more work is needed to definitively declare it a cause, and said studies may identify other potential causes of the injuries as well.
Nonetheless, Dr Schuchat said: 'These findings are significant, ' in the Friday press briefing. Another MMWR report published today, found through a survey conducted in IL, that patients who had EVALI were about nine times more likely to have gotten their products from informal sources such as a friend, a family member or the black market. According to the CDC, 2,051 people have been sickened by the condition dubbed "e-cigarette, or vaping, product use associated lung injury", or EVALI.