Officials announced on Aug. 23 that all New York City public school teachers and other staff members would be required to get vaccinated against the coronavirus by Sept. 27th, as the nation’s largest school system prepares to begin.

The nation’s most populous city is the first to impose a mandatory vaccine for a large group of public workers. Unions reacted angrily to the new demand, claiming that the city should discuss rather than impose. AP reported that two of the city’s largest workers’ groups were considering filing a labor complaint or taking legal action.

Employees must submit proof of their first dose of the vaccine to the Department of Education (DOE) Vaccination Portal. The portal allows all employees and students to check their vaccination status and provide proof of vaccination. In addition, an image of a vaccination card, an NYS Excelsior Pass, or another official record can be uploaded.

An arbitrator has determined that the city must accommodate workers with medical conditions or religious beliefs that prevent them from receiving the COVID-19 vaccination. According to the New York Post, the decision was a setback for Mayor Bill de Blasio’s vaccine mandate for all teachers without exception.

“Keeping our students and staff healthy is our top priority,” said Mayor Bill de Blasio. “To keep our schools healthy and safe, we are now requiring all Department of Education staff to have at least one dose of the vaccine by Sept. 27. Together, we will create a safe and welcoming school experience for our kids.”

The ruling, issued on Friday, Sept. 10, just days before the start of the new school year, states that public school instructors who refuse to get immunized against COVID-19 must receive unpaid leave or a severance package.

Teachers who resign because they refuse to be vaccinated will not be dismissed right away; they will be able to take unpaid leave and be covered by health insurance until Sept. 2022, the decision reads.

Teachers vaccinated while on leave without pay and submitting proof of vaccination to the DOE before Nov. 30 have the right to return to the same school as soon as possible, the ruling states.

“As a group, teachers have overwhelmingly supported the vaccine, but we have members with medical conditions or other reasons for declining vaccination,” United Federation of Teachers President Michael Mulgrew said after the ruling.

“After our demand for independent arbitration, the city backed off its initial position that all unvaccinated personnel be removed from payroll, and will offer out-of-classroom work for those with certified medical or other conditions.”

“The city has also agreed—based on the arbitrator’s determination—to create both a leave process and a severance agreement for other teachers who feel that they cannot comply with the vaccination mandate,” Mulgrew added.

The unions claim in their suit that they “support vaccination and encourage all employees to vaccinate if they are able,” but claim the mayor’s rule is “poorly-conceived” and “coercive.”

The DOE praised the arbitrator’s decision as fair and supportive of the vaccine mandate.

“Given federal and state law, we believe we had to provide a narrow religious exemption,” a DOE spokeswoman said.

“We are pleased with the arbitration and always supported narrow and specific accommodations for those with valid medical and religious exemptions!,” the spokeswoman said. “This is consistent with what our medical experts believe is appropriate, and what we always knew would be part of the impact bargaining for our vaccine mandate.”