(CNN) New York City Mayor Bill de Blasio announced Monday that all Department of Education staff for public schools across the city must be vaccinated against Covid-19, without a testing alternative.
The landmark step, which came less than an hour after the US Food and Drug Administration granted full approval to the Pfizer/BioNTech Covid-19 vaccine, makes New York City the largest public school system in the US to mandate vaccines.
The mayor had previously announced that the city's entire municipal workforce, including teachers, must get vaccinated or go through weekly testing by September 13. With this new mandate, though, all school staff are required to provide proof of vaccination of at least one dose of the Covid-19 vaccine by September 27, the mayor said.
The NYC Department of Education employs 148,000 people and serves 1.1 million students in over 1,800 schools within the education system. At least 63% of of these employees are vaccinated, the department's Chancellor Meisha Porter said.
"This vaccine mandate is already on top of the multi-layered measures we already have in place which have made our schools some of the safest places to be during Covid," Porter said Monday. "Universal mask usage, physical distancing, health screenings, testing and improved ventilation, increased hygiene and oversight by the situation room -- they all work together to provide comprehensive protection for our children."
New York City's Department of Health Commissioner Dave Chokshi said the mandate will help with their layered approach to safety.
"This year we have a powerful new layer of safety in vaccination. Covid-19 vaccination among teachers and other staff as well as all eligible students is a critical strategy to get us back to school," Chokshi said.
Citywide, about 76% of adult residents have had at least one dose of a Covid-19 vaccine, according to city data.
The head of the United Federation of Teachers, the labor union that represents most NYC public school teachers, said in a statement the details of the mandate must still be negotiated.
"Our first priority is keeping our kids safe and the schools open. The city's teachers have led the way on this issue, with the great majority already vaccinated," UFT President Michael Mulgrew said.
"While the city is asserting its legal authority to establish this mandate, there are many implementation details, including provisions for medical exceptions, that by law must be negotiated with the UFT and other unions, and if necessary, resolved by arbitration."
The teacher vaccine mandate is particularly important because children under age 12 are not yet eligible to be vaccinated. Vaccinating all teachers would help create an immune shield around these unvaccinated students and help ensure schools can remain open and safe this coming school year.
The idea of a vaccine mandate is to provide a metaphorical stick that officials hope will push teachers to get vaccinated or face economic consequences. Still, the mandate will be difficult to implement and could lead to worker shortages if enough educators refuse the shot.
The mayor said he was not worried about teacher resignations stemming from the vaccine mandate.
"I feel confident that this is going to work, we're going to see a lot of our teachers and other school staff get vaccinated as a result of this mandate," de Blasio said Monday.
He added: "a lot of teachers and other professionals yearn to work in the NYC public school system for a lot of reasons, including the way we compensate."
Under de Blasio, New York City has been at the forefront of requiring the Covid-19 vaccine. Earlier this month, NYC began to require proof of vaccination to enter all restaurants, fitness centers and indoor entertainment venues, though enforcement won't begin until next month.
"If you're unvaccinated, unfortunately, you will not be able to participate in many things," de Blasio said then. "If you want to participate in our society fully, you've got to get vaccinated."
The vaccine mandate is also part of de Blasio's vaccine-focused strategy at this phase of the pandemic. New York City has recommended mask wearing but stopped short of issuing an indoor mask mandate, a contrast from other major metropolitan areas like Washington DC and Los Angeles County.
"The overwhelming strategic thrust is vaccination, so we thought the right mix was to heavily focus on vaccination, continue to climb the ladder with more and more vaccine requirements in place, and to give a very clear message to all New Yorkers strongly recommending mask usage regardless of vaccination status," de Blasio said in early August.