The judge's ruling Friday means the mandate -- which required all New York City Department of Education employees to provide proof of at least one dose of a Covid-19 vaccine by Monday -- may not go into effect at its planned deadline, unless the case is reviewed before then.

Unions representing teachers, principals and supervisors had said the mandate's introduction has been so poorly handled that many school employees would be suspended.

Currently, more than 82% of Department of Education employees are vaccinated, Filson said, "and we continue to urge all employees to get their shot by September 27."

New York City Mayor Bill de Blasio announced the mandate in August, after the US Food and Drug Administration granted full approval to the Covid-19 vaccine by Pfizer/BioNTech, making educator vaccination a key pillar of the Covid-19 mitigation strategy by the nation's largest school district.