By Alan Gionet

(CBS4) – As more Coloradans get vaccinated, an unvaccinated group is seeing a worrisome increase in cases. The case rates for people between 11 and 17 have more than doubled since the start of April.

“We’re seeing more children who are either diagnosed or admitted. … That’s been going on for the last several weeks,” said Dr. Reginald Washington, chief medical officer at Rocky Mountain Hospital for Children.

READ MORE: 50% Of Coloradans Fully Vaccinated Against COVID, Hospitalizations Reach Lowest Level Since October

Washington noted they are the unvaccinated. With older Coloradans getting vaccinated, the young are left to face the disease as it begins to spread more easily.

“We do believe that the new variants are more contagious so it’s easier to get COVID.”

“We’re also seeing an increase in those younger children, those in that 3-year-old to 10-year-old age group. It’s not as dramatic of an increase, not as steep,” said state epidemiologist Dr. Rachel Herlihy. “We’re also seeing an increase in school associated outbreaks across the state for the last several weeks we have seen that increasing trend as well.”

Among those getting treated in Colorado hospitals is 16-year-old Liliana Cuevas. At first it seemed like a regular head cold. She was tested and her doctor found she was infected with the coronavirus. Then she got terrible stomach pains.

Her mother, Maria Alverado took her to an ER, where they found Liliana had serious kidney problems related to COVID. She was admitted to Rocky Mountain Hospital for Children, where she spent 11 days. Much of it Liliana doesn’t remember.

“It’s scary, it was very scary,” said mom, Maria. “It’s just a terrible experience seeing your kid lying there and there’s nothing you can do to help them or take the pain away. It’s a terrifying experience, it really was.”

READ MORE: 40% Of Colorado COVID Cases Are New, More Transmissible Delta Variant, Health Officials Say

Her mother was told Liliana might need to be put on a ventilator, but that never came about. Last Saturday, she was released, feeling much better.

This week, she went back to school. That brought new challenges. On Tuesday, kids in her class were laughing about COVID. It wasn’t funny, it hurt her.

“It kind of make me mad because I was literally in the hospital hooked to all these machines, just trying to get better and feel better,” said Liliana. “It’s something not to joke about. And it is a very real disease and teenagers can get it.”

Her mother now says she’ll plan on getting her vaccinated.

Washington notes that children as young as 16 can get vaccinated. And he advises other precautions.

“Make sure your kids wear masks when recommended. Make sure they socially distance with people outside their immediate family … If a child doesn’t feel well keep them away from others until they’re over it.”

He pointed out how treatments have improved and vaccines are helping, but he still recognizes the risk even though the young have not been hit as hard as older people.

MORE NEWS: Delta Variant Makes Up 40% Of COVID-19 Cases In Colorado, Health Department Says

“They generally do very well when they get COVID, but there’s a subset that will not do well and since we don’t know ahead of time who’s going to do well and who is not, we need to be very respectful of COVID.”

Alan Gionet