Nov. 7 (UPI) -- The reported number of U.S. vaping-related deaths has increased to 39, up by five since last week, the Centers for Disease Control and Prevention said Thursday. The agency said more deaths are under investigation.
Meanwhile, the number of lung-injury cases surged to 2,051 in 49 states, Washington, D.C., and the U.S. Virgin Islands, up 163 over last week, the CDC said.
Federal health investigators from that agency and the U.S. Food and Drug Administration still have not confirmed what agents or combination of agents could be causing the lung illness, which they have named "e- cigarette or vaping product use-associated lung injury," or EVALI.
"No one compound or ingredient has emerged as the cause of these illnesses to date; and it may be that there is more than one cause of this outbreak," the CDC said on its website.
The median age of patients who died was 53 years and their ages ranged from 17 to 75 years, the agency said.
Meanwhile, a proposed federal ban on flavored nicotine vapes sold in convenience stores seemed imminent after White House adviser Kellyanne Conway told reporters Wednesday the administration would announce its policy "very soon."
A study released this week showed that one-in-four high school students used e-cigarettes. The government-led study, published in the Journal of the American Medical Association also showed 1-in-10 middle school students vaped regularly.
Another study released Tuesday showed teens and tweens preferred sweet-tasting vape flavors like mango, mint and fruit.
Investigators continue to note a correlation with patients who smoked THC vape cartridges and lung injury, but some researchers believe there is a possibility that "dual users" of nicotine and THC vape cartridges are at highest risk.
Meanwhile, the head of a university tobacco and health-related organization complained that the investigation is being hamstrung by federal rules that prohibit investigators from buying THC cartridges legally.
"The DEA is obstructing figuring out what is causing electronic cigarette/vaping lung injury (EVALI); someone high up needs to order them to stop," Stanton A. Glantz, director of the University of California-San Francisco-based Center for Tobacco Research Control & Education wrote in an opinion piece.
Federal law enforcement rules prevent universities from working with any THC products that have not been specifically developed for research, Glantz said.
Researchers would like to find out whether EVALI is related to "dual users" of THC and nicotine vapes, he wrote.