Dozens of new tests appear to confirm that vitamin E acetate is the likely culprit in the vaping-related lung illness epidemic that has sickened more than 2,500 people but appears to be on the decline.

The U.S. Centers for Disease Control and Prevention analyzed 51 fluid samples from victims’ lungs and found the oily substance – used to dilute cannabis vape oil – in 48 of them, the agency said in a study published Friday.

The samples were from 16 states and were compared to nearly 100 samples from healthy people, leading the CDC’s Principal Deputy Director Dr. Anne Schuchat to say the agency is confident the chemical is “strongly linked” to the illnesses.

“We are of the belief that vitamin E acetate has caused the EVALI syndrome in the vast majority of cases,” Schuchat said, referring to the acronym for the illness, e-cigarettes, or vaping products associated lung injury.

Vitamin E acetate can be used by illicit drug-makers to stretch out their supply of marijuana oil. The oil has about the same viscosity as vitamin E acetate, so people can mix the two without it being obvious that they did so. They cannot do the same thing with nicotine liquids because they are far less thick.

The CDC has previously analyzed extracts from the lungs of 29 severe lung illness patients and found vitamin E acetate in each one.

Schuchat stressed that the vitamin E acetate findings explain the dramatic spike in lung injury cases that started this summer, not all possible lung illnesses connected to vaping. In a separate analysis published Friday in the New England Journal of Medicine, the CDC found there were other lung illness cases before the outbreak.

The CDC also has announced that the epidemic is clearly on its way out.

Researchers used an emergency room visit database covering 47 states to identify all visits since January 2017 that were likely to be for vaping-related lung illness. They found a swift rise in new cases reported every week that began in June, spiked in September and has been going down ever since.

As of Wednesday, 2,506 people in 50 states, Washington, D.C., and two U.S. territories have fallen ill with the lung disease, the agency said, and 54 have died.

The week of Sept. 15 saw the most reported admissions nationally, with 214 cases. Last week, meanwhile, saw 97 new cases.

There have been 20 total cases in Oregon, including two deaths. There have been no new cases in at least two weeks.

If vitamin E acetate is indeed causing the lung injuries, it is still unclear how. Studies on animals, which the agency said are already under way, will show how inhaling the chemical affects breathing.

In a separate report, the CDC said there have been 31 cases of vaping-related lung injury patients leaving a hospital only to fall ill again. Another seven have died after leaving the hospital. These patients were more likely to have underlying health problems, the agency said, such as heart disease and diabetes. The agency now recommends that doctors follow up with patients 48 hours after they leave the hospital.

-- Fedor Zarkhin

fzarkhin@oregonian.com

desk: 503-294-7674|cell: 971-373-2905|@fedorzarkhin

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