NASHVILLE, Tenn. (AP) — Children now make up 36% of Tennessee’s reported COVID-19 cases, marking yet another sobering milestone in the state’s battle against the highly contagious delta variant, Health Commissioner Lisa Piercey said Wednesday.

“We had 14,000 pediatric cases in the last seven days, which is a 57% increase over the week prior,” Piercey told reporters. “Right now, 36% of all of our cases in the state are among children when it’s historically been in the 10 to 15% range.”

According to researchers from Johns Hopkins, Tennessee ranks sixth in the country for new cases per capita. The rolling average number of daily new cases has increased by about 2,200, an increase of 75%, over the past two weeks.

Piercey said the biggest increase has been among school-age children just as many are kicking off the new school year.

This spike has raised calls from some health officials for the state to take more forceful protective measures to prevent the spread the virus among young children, teachers and other staffers.

However, Gov. Bill Lee has thus far resisted such suggestions. Instead, he recently signed an executive order letting parents opt their children out of coronavirus-related mask mandates in K-12 schools just as a few school districts issued mask requirements for students and others.

When pressed Wednesday if the Republican was considering giving schools more flexibility to hold virtual learning, Lee said no.

“We don’t have any plans to do that yet,” he said.

Currently, students can only attend remote learning if their district has adopted a specific virtual school — which not every district has implemented. Lee could authorize an emergency order allowing schools to expand their virtual learning options, but thus far chosen has not to do so.

Numerous schools have since been forced to close their doors for days at a time due to the increasing amount of students and teachers testing positive for the virus or having to quarantine.

“If you want to protect your kid from the virus or from quarantine, the best way to do that is to have your kid in school with a mask. At the same time, I fundamentally believe parents should individually make that decision for their children,” Lee said. “It’s a way forward that will provide for parental choice but encourage the safety of our children moving forward.”

Few school districts have adopted a mask mandate as Tennessee’s vaccination rates remain among the lowest nationally. Those districts include Nashville and Shelby County, the latter the largest school district in the state. Some smaller school districts have as well.

Public health experts say masks are a key coronavirus-prevention tool that does not pose health risks for children older than toddler age and are most effective when worn by a larger number of people. The U.S. Centers for Disease Control and Prevention has again recommended them for schools. Currently, only those 12 and older are eligible for COVID-19 vaccines.