The Los Angeles Unified School District's Board of Education voted unanimously to mandate the COVID-19 vaccine for all eligible students.
The vote is a landmark move for the nation's second-largest district, which has over 600,000 students and operates 1,200 schools in the LA area.
All students ages 12 and up will be required to be fully vaccinated by Jan. 10, 2022, unless they have a "medical or other exemption," the school district said.
The resolution had initially called for all students ages 12 and up to be fully vaccinated no later than Dec. 19.
"The science is clear -- vaccinations are an essential part of protection against COVID-19," Interim Superintendent Megan K. Reilly said in a statement following the vote. "The COVID-19 vaccines are safe, effective and requiring eligible students to be vaccinated is the strongest way to protect our school community."
The majority of board members had said they would approve the measure or were leaning toward it, the Los Angeles Times reported.
Prior to the vote, the district had said passing the proposal "will result in the safest school environment possible and minimize disruption to full-time, in-person instruction brought about by the COVID-19 pandemic."
Children ages 12 and up are only eligible for the Pfizer COVID-19 vaccine. Though the Pfizer vaccine was fully authorized by the U.S. Food and Drug Administration last month, it remains under emergency use authorization for individuals 12 through 15.
The vote came a week after LA County health officials said more than 5,200 COVID-19 cases were detected among K-12 students in the county over the past two weeks. The county's public health director, Barbara Ferrer, called the number "sobering."
Just before the board voted, county health officials reported there were 5,599 student cases so far this school year, as of Tuesday.
The district's COVID-19 testing dashboard shows 1,357 positive cases among students and staff and a staff and student case rate of 9.93 per 100,000 residents, significantly lower than the county case rate of 20.03 cases per 100,000 individuals.
So far in LA County, over 60% of 12- to 15-year-olds have received at least one dose of the vaccine and 68% of 16- to 17-year-olds have received at least one dose, according to the county's vaccine tracker.
Nationwide, pediatric hospital admissions remain at one of their highest points of the pandemic, with more than 2,200 children receiving care across the country for confirmed or suspected COVID-19. Additionally, the average daily COVID-19 case rate is now higher among children and adolescents ages 5 to 17 years than all adult age groups.
All Los Angeles Unified School District teachers and staff are already required to be vaccinated by Oct. 15.
A Los Angeles high school English teacher who spoke to ABC News' "Start Here" podcast said she "wholeheartedly" agreed with the mandate. The teacher asked ABC News not to include her name in this report because she's not authorized to speak publicly on the school board's decision.
"I'm really hoping that the students will become the focus of vaccinations because employees were mandated from the district to get vaccinated. ... And we have to upload our vaccination cards by the deadline," she said. "I already did mine. I was fully vaccinated at the end of March."
She said that weekly COVID-19 testing feels disruptive in her classroom. With the rigorous testing protocol and quarantine requirements when a student tests positive, she said she hasn't been able to fill a class yet.
"It's a revolving door of students. I probably have a third of my students absent in each class because of their close contact with someone who tested positive," she said.
The move to mandate student vaccines was also supported by the United Teachers Los Angeles union, which represents more than 30,000 teachers, counselors, nurses and librarians.
The union said in a statement last week, "UTLA announced support for a vaccine mandate for eligible students. ... This aligns with UTLA support for the educator vaccine mandate implemented by LAUSD and will keep our schools safer as well as positively contributing to the higher community vaccination rates needed to reverse the surge in infections."
LAUSD is already facing legal backlash for its robust COVID-19 safety measures currently in place, including requiring weekly testing for all students and employees, masks indoors and outdoors and requiring all employees to be vaccinated.
Passing a vaccine mandate may bring an onslaught of further legal challenges.
Mandates related to the pandemic, such as requiring face coverings in classrooms, have led to lawsuits and heated debates between school districts, parents and lawmakers, as in Texas and Florida.
Los Angeles would not be the first to impose a vaccine mandate.
It was already adopted by the Culver City Unified district with a Nov. 19 deadline to take effect, in anticipation that the FDA will grant full approval for school-aged students to get the vaccine, local Los Angeles ABC station KABC reported.
In the Oakland Unified School District, Sam Davis, the Vice President of the Board and Director of District 1, proposed a vaccine mandate at a board meeting Wednesday night. The proposal will be discussed at a Sept. 22 meeting with a potential vote, he told ABC News.
"Vaccination is key to keeping teenagers healthy, in school and learning, and keeping their families healthy as well," he said during the meeting. "We're lucky to live in a place with comparatively high vaccination rates. In Oakland, 73% of those aged 12-17 have received at least one dose, compared to less than 50% nationwide. So we're doing well but we could do much better."
It's too soon to tell if other districts will follow suit.
New York City Mayor Bill de Blasio said in a press conference Thursday there are no plans for a vaccine mandate for eligible students in the city, which has the largest school district in the nation.
"We just don't think that's the right thing to do ... but teachers are mandated to," he said. "We can keep any option on the table, but right now, no. We want every kid in school."
Similarly, in Chicago, which has the third-largest school district in the nation, Mayor Lori Lightfoot said during an Aug. 30 press conference that a vaccine mandate for students would be "premature."
"Obviously we don't have a vaccine for children who that younger than 12, so it's a little premature I think to be talking about that," the mayor said.