A total of 440 students have been quarantined in Palm Beach County, Florida, due to COVID-19, just two days after the start of the school year, the Palm Beach County School District told ABC News.
The district kicked off the school year with in-person classes on Tuesday for the first time since last March.
The district requires facial coverings inside schools and buses for all students, unless their parent opts out of the requirement, as well as staff.
But that didn't stop the virus from affecting the return to school.
So far, there are 134 confirmed COVID-19 cases -- 26 among employees and 108 among students -- within the school district, according to its COVID-19 dashboard.
The district told ABC News 6,379 students out of its estimated 167,000 pupils, or about 3.8%, have opted out of wearing masks as of Thursday.
Student Caden Hart, a sophomore at Dwyer High School, is one of the pupils quarantining after both of her parents tested positive for the virus.
"Getting a late start is a scary thought," she told local Florida ABC affiliate WPBF, reported.
"A part of my brain is definitely like, 'Oh, I don't have to go to school. I can sleep in,'" she said. "But the majority of me is really concerned about being left behind this year."
She's worried not just for herself, but for other students who will struggle with quarantining and potentially falling behind.
"What happens when kids start getting COVID again?" she asked. "And they're missing two weeks of school, and they're missing all of these lessons and stuff that they're going to need."
District Superintendent Michael J. Burke said that he'll revisit the facial covering requirement every 30 days and adjust accordingly. Currently the school does not offer the same level of virtual learning that it did last year, this year students do have the option for virtual school, but it is independent and does not have live instruction, Burke said.
"The governor's got to take responsibility for establishing the ground rules we're operating under," Burke said on MSNBC Thursday. "And this ability for families to opt out is leading to more cases, which is ultimately going to send more kids home and deprive them of that traditional classroom experience."
Last month, DeSantis issued an emergency order giving parents the final say over masks for kids in school. In a press conference last month he said Florida students shouldn't be "muzzled" during the school year, adding, "We need them to be able to breathe."
Several state leaders have sparred with the public over mask mandates in schools.
The state reported 134,506 new cases the week of July 30 to Aug. 5 and 175 deaths, with a new case positivity rate of 18.9% Among the new cases, more than 27,000 infections were among school-aged children, meaning those 19 years old and younger, according to the state's latest COVID-19 report.
There were 15,358 confirmed COVID-19 hospitalizations Thursday, according to the Florida Hospital Association, quickly surpassing its Monday count of 14,000.
"In the past week, Florida has had more COVID cases than all 30 states with the lowest case rates combined," White House COVID-19 Response Coordinator Jeff Zients said Thursday. "And Florida and Texas alone have accounted for nearly 40% of new hospitalizations across the country."