More than 800 students and 42 teachers and staff in Cherokee County are quarantining after coronavirus was reported at 19 different schools, the school district announced late Monday.

The number of students quarantining jumped by 300 from the start of the day, when the district reported 478 in quarantine due to COVID-19 infections reported at various schools.

The district's updated note Monday evening said 38 students and 12 teachers and staff tested positive for the virus. 

At Etowah High School, nearly 300 students of the 2,400 total student population were quarantining. Etowah was one of the high schools last week where photographs went viral after dozens of students crammed together in front of the building without masks to celebrate their first day of school.

The skyrocketing number of students in quarantine comes as a group of parents plan to hold a rally Tuesday morning at Cherokee High School to support teachers and the district's in-person reopening plans.

MORE: Parents Rally In Support Of Cherokee County Schools In Face Of Growing COVID-19 Cases

Earlier Monday, Gov. Brian Kemp ruled out a mask mandate for schools and said he believes the reopening of classrooms across Georgia has gone “real well," with the exception of viral photos shared on social media that showed students crowded together.

"I think, quite honestly, this week went real well other than a couple virtual photos," Kemp said.

RELATED: Kemp Says School Openings in Georgia Are Going 'Real Well'

With many schools reopening last week, reports of children testing positive for coronavirus have stretched from Columbia County near Augusta to as far south as Lee County near Albany.

North Paulding High School – where photos of students packed shoulder-to-shoulder brought national scrutiny – shut down Monday and Tuesday for a deep cleaning after six students and three staff members tested positive. 

The governor sought to downplay reports of coronavirus cases at schools, saying, "There’s definitely going to be issues when you open anything, we saw that when we opened businesses, we’re seeing that when we open schools." He added that the state has worked with superintendents "to really give them the tools that they need to open the classroom."

"I'm a firm believer that the local governments know their schools better than the state government does," Kemp said. 

Research has shown children suffer milder symptoms than adults, but they can contract the virus and spread it, putting parents, teachers, caregivers and others at risk.

Phillip White, a 68-year-old grandfather with serious lung and heart disease, fumed last week after learning his granddaughter might have been exposed to coronavirus in her Cherokee County kindergarten class.

“They literally sent me a potential death sentence home from school,” White said.

Georgia has recorded more than 219,000 coronavirus cases since the pandemic began, including over 4,200 deaths. Over the last four weeks, the data has shown nearly 100,000 people tested positive for COVID-19 in the state and that nearly 1,200 people died, including a 7-year-old boy.