Kevin Boclair should have been starting his sophomore year at Bloomsburg University at the end of August.

Instead, he was laid up in a hospital bed, having coughed so much and so hard that he blew tiny holes in his lungs and his chest filled with air.

Days later, the 19-year-old wasn’t getting better, and his doctor came in to talk.

“Kevin, to be honest, a kid your age should be doing better by now,” Kevin’s mother, Debbie Boclair of Broomall, recalled the doctor telling her son. “We’re wondering if there’s anything in your life that may be affecting you that could be making this worse.”

Kevin looked over at Debbie, Debbie left the room, and Kevin confessed: He’d been vaping the equivalent of a half-pack of cigarettes a day for over a year.

More than 200 people in 25 states have contracted severe lung illnesses potentially associated with vaping, according to the U.S. Centers for Disease Control and Prevention, which is investigating the cases. There have been 14 reported cases in Pennsylvania and at least nine in New Jersey. One death in Illinois is believed to be connected to vaping.

The string of cases has rattled the medical and public health community because a majority of the patients have been young adults and teens who are otherwise healthy. Even as the number of cases grows, the CDC has been unable to identify a specific product or substance to link them all, spurring increasingly strong reactions from public health agencies.

“While this investigation is ongoing, if you are concerned about these specific health risks, consider refraining from using e-cigarette products,” the CDC wrote in a public health alert issued Friday.

Last week, Milwaukee urged people to stop using e-cigarettes immediately, and this week, Michigan became the first state to ban flavored vaping liquids, which have been criticized for targeting youth by simulating candy and fruit flavors.

Several cases have been associated with using e-cigarettes to vape cannabis products, and the CDC has warned people against altering e-cigarettes or using them with vaping products purchased off the street. Other patients have reported falling ill after using e-cigarettes as intended.

“Even though cases appear similar, it is not clear if these cases have a common cause or if they are different diseases with similar presentations, which is why our ongoing investigation is critical,” the CDC and the U.S. Food and Drug Administration said in a joint statement Friday.

» READ MORE: Vaping, e-cigarettes linked to 215 cases of severe lung illness in 25 states, including Pa., N.J.

The cases share a set of pneumonia-like symptoms, including difficulty breathing and coughing. Some patients develop symptoms slowly, while others experience a sudden onset of illness.

After her son had been shuffling around the house for a few days with what seemed like a cold, Debbie, a nurse at Main Line Health, took him to Bryn Mawr Hospital when he came down to breakfast two weeks ago ashen-faced and coughing uncontrollably.

As his condition worsened, he was transferred to Lankenau Medical Center and then to the Hospital of the University of Pennsylvania. His doctors feared he might need a lung transplant.

Kevin told his parents and doctors that he had started using an e-cigarette with candy-flavored vapors, then switched to nicotine — and then couldn’t stop. On a few occasions, he tried a friend’s e-cigarette with cannabis, Debbie said.

Debbie, 56, and her husband, Len, 55, first caught Kevin with an e-cigarette when he was 17. They took it away, grounded him, and tried to explain why they didn’t want him vaping by pointing to themselves as examples.

Debbie tried cigarettes when she was 13 and smoked for more than 25 years. She and Len, who started smoking when he was 21, tried to quit several times before giving it up for good when Kevin was 2. They didn’t want Kevin and his brother, who is 18 months older, to grow up thinking smoking was acceptable.

“Here’s the thing I thought about yesterday: We both did smoke, and it took a lot of years for us to realize smoking is really not good for you. This kid vaped for what looks to be about a year and a half, and — bam,” Len said Wednesday.

» READ MORE: Tips for talking to teens about vaping

E-cigarettes are often marketed as an alternative to combustible cigarettes that can be used as an aid to help smokers quit.

Kevin is an avid internet researcher, his mother said, and from his hospital bed played his parents a video he and his friends watched that compared the effects of cigarette smoke and e-cigarette vapor on cotton stuffed in clear jars. Cigarette smoke turned the cotton brown, gunky, and gross. The vapor didn’t.

“We really didn’t think it would hurt us," he told his parents after the video finished playing.

But the CDC warns that e-cigarette vapor can contain nicotine and other potentially harmful chemicals. Scientists are still learning about the short-term and long-term health effects of e-cigarettes.

A study published last month by researchers at the University of Pennsylvania found that e-cigarettes can cause short-term damage to blood vessels, causing inflammation and stiffness — even when the vaping liquid does not contain nicotine. The study concluded that more research is needed to understand the long-term effects of vaping on blood vessels.

“It was advertised as a safer alternative to tobacco smoke, but it’s not harmless,” said Alessandra Caporale, a post-doctoral researcher in radiology at Penn Medicine and the study’s lead author.

Nearly two weeks after he was hospitalized, Kevin is on a breathing machine, sedated, so his lungs can recover. He is in critical but stable condition. It’s unclear when he’ll be well enough to go home.

When they’re not at their son’s bedside, Len and Debbie are making a public plea to anyone who will listen. They first shared their story with 6ABC, and have encouraged friends and family to share a Facebook post about Kevin’s experience.

“If you’re doing it, please stop. If you’re a parent, hound your kids,” Len said.