The teen, from Nottingham, UK, says the ordeal is also to blame for mental health issues.
The teen says his grandfather is now fitter than him. Photo / Facebook
"I wouldn't even say they're at 60 per cent," Ewan said, referring to his lungs.
"I used to be really healthy. I used to run every night and I can't do anything any more. When it's hot it messes with my lungs. I'm on steroids to help them cope."
"My life's changed massively," he said. "When I was in hospital they said I had the lungs of an 80-year-old lifelong smoker and I'd only vaped for five or six months."
His family has released photos showing his time in intensive care in hospital.
He now travels around the UK talking to children about he dangers of vaping. He's had to give up his professional boxing dreams and is now hoping to train towards becoming an accountant.
His family released photos showing him in intensive care. Photo / Supplied
He says the flavours make vaping particularly attractive to teens.
"When I went into the hospital they took my vape and I was vaping blue flush (blackberry flavour) and I had a rhubarb and custard one too.
"It's that sort of stuff that got me addicted. Those sweet flavours are addictive and they entice young people."