As the number of reported vaping-linked lung illnesses has eclipsed 2,500, CDC researchers are narrowing in on a likely cause for the vast majority of cases.

Cases of vaping-linked lung illness surpass 2.5K

CDC data updated Tuesday shows the number of reported hospitalized cases of a lung illness officials believe is linked to e-cigarette use and vaping, dubbed EVALI, reached 2,561 as of Dec. 27, 2019. There were 55 confirmed deaths related to the vaping-illness as of Dec. 27, 2019, according to CDC. Cases of the illness have been reported in all 50 states, Washington, D.C., and two U.S. territories, with deaths confirmed in 27 states and the District of Columbia.

New data further suggests vitamin E acetate is linked to majority of cases

CDC last month released four separate reports highlighting new data on the vaping-linked illness. Based on that data, Anne Schuchat, CDC's principal deputy director, said the agency has determined that the majority of cases of EVALI "can be attributed to exposure to [tetrahydrocannabinol (THC)]-containing vaping products [with] vitamin E acetate."

For one report published in the New England Journal of Medicine, researchers analyzed lung fluid samples from 51 patients with EVALI in 16 states, a majority of whom used THC-containing vaping products, as well as lung fluid samples from 99 healthy patients who either vaped only nicotine, exclusively smoked traditional cigarettes, or did not ever vape or smoke.

The researchers found vitamin E acetate in 48 of the 51 lung fluid samples from patients with EVALI, but found no presence of vitamin E acetate in the lung fluid samples of healthy patients. According to the Washington Post, the findings reinforce officials' already-presumed connection between vitamin E acetate and EVALI. 

However, Schuchat said CDC has not ruled out other potential culprits for the illness.

For instance, researchers in a separate report published in the New England Journal of Medicine said the release of new-generation e-cigarettes containing nicotine salts—which allow users to inhale higher levels of nicotine with less irritation to the throat than other substances—could have contributed to cases of the illness. The researchers, who examined data on ED visits from the National Syndromic Surveillance Program, found that ED visits for vaping-related lung injuries surged in June 2019, reached a peak in September 2019, and then started to decline. The researchers noted a number of factors might have led to the surge in EVALI cases, including an increase in the use of e-cigarettes containing nicotine among U.S. high school students, as well as increased use of e-cigarettes containing nicotine salts.

Schuchat said CDC is continuing to investigate the illness and the health effects of e-cigarettes, including the effects of inhaling the aerosol and gases released by e-cigarette fluids.

CDC warns of patient relapses, updates treatment recommendations

Meanwhile, CDC in a Morbidity and Mortality Weekly Report (MMWR) published last month noted that 31 of the 1,139 hospitalized patients with EVALI who were discharged by Oct. 31, 2019, had to return to the hospital within a median time of four days after their initial discharge, and seven of the 1,139 patients died within about three days of their initial discharge. Federal health officials said EVALI patients with a history of chronic conditions such as diabetes, heart disease, and respiratory problems were more likely to be readmitted to the hospital, and patients ages 50 and older were more likely to die after being discharged.

Schuchat said it is unclear whether the patients who were readmitted or died had started vaping again after their initial discharge.

Based on the latest data, CDC in a separate MMWR published last month updated its recommendations for clinicians treating patients with EVALI. The agency now recommends that providers conduct an inpatient follow up with EVALI patients who had been hospitalized within two days of the patients' discharge (Weixel, The Hill, 12/31/19; Sibi Joseph, Reuters, 12/31/19; Sun, Washington Post, 12/20/19; Harris, "Shots," NPR, 12/20/19; O'Donnell/Alltucker, USA Today, 12/20/19; Grady, New York Times, 12/20/19).