Rylie Whitten was a happy, healthy teenage girl before she came down with one of the worst cases of toxic shock syndrome the state of Michigan has ever seen, according to news reports.

The 15 year old has been in serious condition at the Helen Devos Children’s Hospital in Grand Rapids after falling ill on Jan. 4th.

“She didn’t feel well, her body was aching, so we kept her home,” Rylie’s father Nathan recalled to the Greenville Daily News. “But then on Tuesday, she started vomiting, so we visited the family doctor.”

Rylie believed she had the flu, but had no temperature or cough. Meningitis and influenze tests came back negative, but after a blood test, Rylie was airlifted to the hospital.

“At that point, they knew she had some kind of kidney failure,” Nathan said. “She was still coherent, still normal Rylie, but then they had to sedate her, because…it took over.”

The teen had toxic shock syndrome (TSS), a rare complication of bacterial infections often associated with the use of super-absorbent tampons. Doctors agreed that this was the case with Rylie. The 15 year old has been on life support for the past week, receiving multiple drugs and kidney dialysis, as well. Rylie’s heart and lungs began to have issues alongside her kidneys, though.

“So, you have the cardiovascular system failing, lungs failing, so it’s pretty serious; in her case, it was very serious,” said Dr. Surender Rajasekaran, who works in the pediatric intensive care unit at the hospital, according to ABC news affiliate WZZM.

Rylie underwent several heart surgeries, and her vitals began to improve. In one 24-hour period alone, Rylie showed important signs of improvement—she has been taken off insulin and blood pressure medications as a result. She has very recently been taken off life support, and is breathing on her own. According to People, Rylie is expected to make a full recovery.

“She’s fought through everything just great…every day has been something she’s had to conquer,” Nathan said.

Though rare, TSS is still a real threat to those who use super-absorbent tampons, have open wounds, or who have recently undergone surgery. Symptoms include many typically written off as flulike, including high fever, headaches, muscle aches, and vomiting, so understanding risk factors is important. Once contracted, the disease can cause organ damage and shock, even resulting in death in 50 percent of cases, according to the National Institutes of Health.