The number of vaping-related illnesses across the country increased again this week, though the jump in cases was smaller than in previous weeks.

On Thursday, the Centers for Disease Control and Prevention reported 2,172 lung injury cases linked to e-cigarette or vape products.

That's an increase of 121 cases from last week. The only state left untouched by the epidemic is Alaska. Health officials in Puerto Rico and the U.S. Virgin Islands are also reporting cases of what's now called EVALI, short for "e-cigarette, or vaping, product use associated lung injury."

The illness has proven deadly for 42 people so far in 24 states and Washington, D.C.

California and Illinois are the states that have reported the largest number of EVALI deaths so far, with four each.

Last week, the CDC said it had found evidence of a synthetic form of vitamin E oil in lung fluid samples from patients. Of 29 samples tested, all 29 had extremely high levels of the oil.

While it's a solid clue in the investigation into what is making people sick, it's not likely to be the only cause.

The age range of patients is from 13 to people in their 70s — but most are men in their 20s and 30s, and most reported vaping products they bought off the street or got from friends that contained THC, marijuana's psychoactive ingredient.

Patients generally have arrived at the hospital gasping for air and coughing, with a high fever, extreme fatigue and gastrointestinal problems. Many have been left with irreversible lung damage. And one patient — a 17-year-old boy in Michigan — needed a double lung transplant to survive.

In September, federal health officials announced they were planning to ban e-cigarette flavors, including mint and menthol. The Trump administration was expected to take some kind of action on vaping this week, but has not yet done so.

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