KNOXVILLE, Tenn. (WATE) — A term you may be hearing more and more about recently is “breakthrough cases.” That’s when someone who has been fully vaccinated still gets COVID-19.

The chances of it happening are slim, but as one Knoxville family recently discovered, it can happen. Dr. Jennifer Mozingo’s family just finished a 10-day quarantine, after her 14-year-old son tested positive for COVID.

He was fully vaccinated and got his second dose in early June. That’s why she said she wasn’t worried, just a little surprised.

“I think it was a week and a half ago that my son had some symptoms that seemed relatively minor at the time, but given the fact that we wanted to be careful we went ahead and did an at-home test and discovered that he was a breakthrough case,” said Dr. Mozingo.

Mozingo said he had a sore throat for a couple of days after that, and congestion, but she didn’t panic knowing it had been at least six weeks since he got his shot. “If you have your child vaccinated and they do get COVID exposure and get COVID but it’s very mild, wasn’t that the whole point,” Mozingo said.

The topic of breakthrough cases is one the Tennessee Health Commissioner talked about just this week, saying it’s important to put the rate at which it’s happening in context.

“Our breakthrough rate in Tennessee is 0.18 percent. That is less than .2 percent of all fully vaccinated Tennesseans are getting infected,” said Dr. Lisa Piercey. “I don’t want you to get in the habit of thinking that vaccine doesn’t matter or that you’re likely to get a breakthrough infection because you’re very, very likely to not do that.”

But as Mozingo can tell you — while rare — it still happens. That’s why she’s reminding others not to dismiss symptoms, even if they’re mild, and even if you’re vaccinated.

“Minor symptoms can still be significant, especially in that population of children,” Mozingo said.

She also said she has no regrets. Her son’s positive test doesn’t sway her opinion about the importance of getting a vaccine. And with this going on as schools start back up, she did also say she would advocate for wearing a mask inside school buildings.

Mozingo’s 14-year-old son is doing better and feeling great.