A teenager who vaped every day for three years was put into a medically-induced coma after her lungs started to deteriorate.

Maddie Nelson, 18, from Nephi, in the US state of Utah, was taken to hospital in late July with a high fever and intense kidney pain.

In the video above: Vaping health alert

She was also struggling to breathe.

“The nurses tried giving her oxygen hoping it would help, but it wasn’t enough,” Nelson’s sister Andrea Fullmer wrote on a GoFundMe page.

Days later, the 18-year-old, who is the youngest sibling in the family, was rushed to intensive care where she could barely draw a breath.

After an X-ray of her chest showed her condition was severe, Nelson’s family and doctors decided to put her in a coma.

Maddie Nelson was barely breathing before being put in a coma. Credit: GoFundMe

“This was a hard decision for us to make, her condition seemed to be getting worse fast and we were scared we may never be able to talk to our sister again,” Fullmer wrote.

It was while she in a coma that doctors diagnosed the teenager with acute Eosinophilic Pneumonia, caused by vaping.

Nelson told FOX13 she had vaped every day for three years.

"I thought vaping was fine," she said.

"I did all the tricks, all the time."

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But it was only after she woke up from her coma that she learnt of the real damage the habit had caused.

"I had fat particles growing inside my lungs that were related to the glycerin in vape juice," Nelson said.

"So then my lungs were full of fluid. They said that my chest X-rays were one of the worst they've ever seen."

Her family had feared the worst. Credit: GoFundMe

But Nelson, who was in the coma for three days, made a massive improvement after being given steroids to combat the inflammation.

Although the teenager initially recovered, she still needs to use oxygen at night and continues to be monitored.

"It's very scary, because the doctors don't know the long term effects of this," Nelson said.

"So they don't know what the healing process is even supposed to be like."