Staff photo by Troy Stolt / Rae Kelly, 5, browses for books in the children's section of the Chattanooga Public Library on Monday, May 3, 2021 in Chattanooga, Tenn.

This story was updated Wednesday, Aug. 11, 2021, at 7:22 p.m. with additional information.

Hamilton County Schools will soon require students to wear masks indoors as the new academic year begins, although parents will have the option of filling out a form to reject the stronger public health measure.

Classes start on Thursday, and staff members will immediately be required to wear face coverings. Students will have until Monday to adjust to the newly-imposed requirement.

The district joins an increasing number of K-12 schools and academic institutions across Tennessee to adopt such a requirement in the face of surging COVID-19 cases, hospitalizations and deaths.

Superintendent Bryan Johnson made the announcement by posting a video Wednesday afternoon.

"As the pandemic has reignited, recommendations from the CDC [Centers for Disease Control and Prevention], health department and local physicians have all been to require students and employees to wear masks in school. Today, we are at 173 per 100,000 cases, which is at the same level we were at last November.

"Face coverings have become a widely debated, overly political topic. We have always deferred to medical expertise and evidence, which is what we will continue to do now," he said.

The face mask requirement is for all students and staff regardless of vaccination status. 

Parents can opt out of the requirement for their child through a form on the parent portal. A news release from the district said more information on accessing the parental opt-out form will be available before Monday, but face coverings will be required for all students on all school buses starting Thursday.

"As a parent of a Hamilton County student, I know firsthand how challenging this news can be for some to hear. We have been committed to ensuring that schools remain open and students remain in classrooms to continue learning and feel this is the best plan forward to accomplish that goal," Johnson said, adding that these are the same protocols that allowed Hamilton County Schools to remain open 90% of last year.

The district will release a revised reopening plan on Thursday, which officials will continue to monitor and adjust based on the evolving pandemic, Johnson said.

In their announcement, officials said the policy is based on recommendations from medical and public health experts, who have been calling on schools to implement universal masking protocols as the highly contagious delta variant drives COVID-19 surges across the country, primarily among the unvaccinated.

(READ MORE: Delta variant spreads in Hamilton County as children lack access to vaccines, schools not requiring masks)

Although children are far less likely than adults to face serious COVID-19 infections, serious and fatal infections can still occur, and children play a key role in transmitting the coronavirus to others.

Hamilton County residents ages 12 to 20 represent the least-vaccinated age group, with 32% of 12- to 15-year-olds and 40% of 16- to 20-year-olds having received at least one dose of vaccine as of Wednesday, according to data from the Hamilton County Health Department. COVID-19 vaccines aren't yet available for children younger than 12.

These same age groups are helping to fuel a dramatic increase in COVID-19 cases, which in Hamilton County have risen from a weekly average of 11 new cases per day on July 1 to 212 cases per day as of Aug. 11.

Demographic data from the Tennessee Department of Health shows that COVID-19 cases in Hamilton County residents ages 11-20 in the weeks leading up to the new school year are on par with the same period last year, and new cases among children age 10 and under are higher than the prior-year period.

Between July 1 and Aug. 9, 2021, 482 new cases in residents age 11-20 were reported — representing 14% of the county's new COVID-19 cases — compared to 490 new cases, which was also 14% of the county's COVID-19 cases during the same period of 2020.

In 2020, children age 10 and under accounted for 7% (231) of cases between July 1 and Aug. 9. Now, that group represents 9% (298 cases), and has also seen the largest increase in new cases among all age groups in the county since July 1.

Last week, Tennessee's top health official said that children's hospitals across the state were already near capacity due to a rise in pediatric COVID-19 infections and increases in other respiratory viruses that children normally contract in the winter.

(READ MORE: Chattanooga child care centers ramp up COVID-19 protocols as cases rise among children)

Unlike last year, COVID-19 vaccines are now available for ages 12 and up, and the county is 43% fully vaccinated — well below the level needed to curb viral spread.

Hamilton County Schools had a mask mandate in place for the entire 2020-2021 school year.

The decision to require face masks in schools comes amid mounting pressure from health advocacy groups and organizations who favor universal masking requirements.

Both the American Academy of Pediatrics and the CDC issued new school safety guidelines in July, which included universal indoor masking of both vaccinated and unvaccinated individuals, including children older than 2.

For weeks, local school officials maintained that they would recommend but not require face masks in the new year. Johnson said the district was still gathering information after a Monday news conference where parents said school officials should follow CDC recommendations.

Gov. Bill Lee, who throughout the pandemic has deferred these decisions to localities, recently shifted his messaging on the issue of masks in schools, saying that parents should be the ones to decide whether their children wear a face covering.

"What I believe is that parents care most about their children, and the health of their children, and the impacts of their children are best up to the parents," Lee told reporters after an unrelated appearance at McConnell Elementary School in Hixson on Wednesday. "Anything that we can do to give parents input, to give parents the choice, to make sure that parents are making decisions, that's what I believe should be happening across the state."

Lee was joined by House Speaker Cameron Sexton, who also on Wednesday sent a letter to Lee calling for a special session so that the General Assembly could "address misdirected and mandated responses to COVID-19 by local entities."

Sexton first suggested he would pursue a special session if schools moved to require face masks last week at a news conference about statewide standardized test results, and Lee told reporters on Monday that "nothing's off the table" when it comes to halting schools' ability to require masks.

(READ MORE: Tennessee Republican House and Senate speakers split on need to bar local school mask requirements)

As the law now stands, elected school boards have the authority to impose mask requirements for students and faculty. The Hamilton County school board voted unanimously early in the pandemic to delegate decisions around COVID-19 protocols to the superintendent.

Shelby County, Hancock County, Henry County, Oak Ridge and Metro Nashville Schools are among the public school districts in the state to implement mask requirements so far this year. 

Though many parents and medical professionals have praised those districts, the decision to require face masks has been met with strong opposition in some instances.

On Tuesday evening, a group of parents erupted in protest at a Williamson County school board meeting after the board voted 7-3 to implement a face mask mandate at elementary schools beginning Thursday.

The CDC and other leading health organizations call face masks one of many "layered approaches," including contact tracing, social distancing and proper hygiene, that are needed to control the pandemic until all children are eligible for COVID-19 vaccines and vaccine uptake improves.

Staff writers Anika Chaturvedi and Wyatt Massey contributed to this story.

Contact Elizabeth Fite at or 615-757-6673. Follow her on Twitter @ecfite.