A worrisome realization is emerging about the more than 1,200 people diagnosed with severe lung injuries related to vaping: Even after they recover, they may be at risk for future breathing problems and hospitalization.
On Friday, the Centers for Disease Control and Prevention said it had identified a "handful" of patients who'd been hospitalized, released and then readmitted.
Indeed, a New York teen who died from the vaping-related illness had been hospitalized twice.
It's unclear why some patients aren't able to recover fully. It could be that the patient resumes vaping, but health officials say there are several other possibilities.
"It may be that the lung injury weakens the lungs to other insults, whether they're infectious or otherwise," Dr. Anne Schuchat, the CDC's principal deputy director, said on a call with reporters.
Or, she said, it may be that patients are weened off the steroids used to treat their injured lungs too quickly.
That's the exact reason doctors gave Anna Ware of Burleson, Texas, when she had to be readmitted after she'd previously been hospitalized with the lung illness linked to vaping.
Ware, 28, tells NBC News she started vaping within the past year as a way to quit smoking cigarettes. She admitted to vaping CBD oil and Juul e-cigarettes, as well as devices containing THC, the psychoactive ingredient in marijuana.
THC has been implicated in a majority of the cases nationwide. The Food and Drug Administration has received more than 700 samples of vape devices or e-liquid from patients for testing, but has so far been unable to link all of the cases to any single ingredient or product.
Health officials have also come up with a name for the illness: EVALI, an acronym for "e-cigarette or vaping product use associated lung injury."
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It’s a degenerative lung disease I’ll have for the rest of my life
Ware started feeling extremely tired back in May, but she attributed the fatigue to being the mother of two children under 6.
But over the summer, her malaise evolved into a bad cough and daily vomiting.
"One day, I just couldn’t breathe any more," Ware said. "I thought I was having a panic attack."
Instead, Ware was diagnosed with pneumonia related to vaping and spent 12 days in the hospital. But within weeks of returning home, she was readmitted with a collapsed lung.
She insisted she did not resume vaping, and instead was forced to quit all forms of smoking cold turkey.
"I’m not smoking anything at all. I can’t. My lungs are so bad," she said.
Since the collapsed lung, Ware has been to the emergency room several more times and been diagnosed with pleurisy, a condition in which the linings of the lungs become inflamed.
She said doctors put her on strict bed rest for the next several months, especially during cold and flu season.
"It’s a degenerative lung disease I’ll have for the rest of my life," Ware said. "If I get a cold, I’ll end up back in the ICU."
Indeed, the vaping-related illnesses should be front and center on doctors' radars moving forward, public health officials said Friday.
Because investigators are learning about the life-threatening lung injuries in real time as patients get sick and are hospitalized, the CDC released guidance Friday for clinicians on identifying, treating and following patients.
Complicating matters for doctors is that vaping-related lung illnesses tend to have the exact same symptoms as sicknesses that typically spike during winter, such as flu and pneumonia: trouble breathing, cough, chest pain, extreme fatigue, fever, vomiting and diarrhea.
The CDC urged doctors to consider both typical lung infections caused by viruses or bacteria, as well as asking patients about vaping.
Patients "may have lung injury, they may have an infection, or they may have both," Dr. Ram Koppaka, medical officer for the CDC's National Center for Immunization and Respiratory Diseases, said during the call.
"It's really about clinicians maintaining a very high index of suspicion for both lung injury as well as infectious causes," he said.
Twenty-nine people have died from the illness, and other deaths are under investigation to determine whether they, too, should be counted among EVALI's victims. The age range of those who have died is quite broad: 17 to 75.
On Thursday, the CDC provided its weekly update on the number of cases it's confirmed nationwide: 1,299 in 49 states, plus Washington, D.C., and the U.S. Virgin Islands. Alaska is the only state that has reported no cases.
The numbers are sure to grow, as state health departments tell NBC News they've either confirmed or are investigating more than 1,700 cases.