US Supreme Court Justice Sonia Sotomayor on Friday turned down an emergency appeal to block a New York City COVID-19 vaccine mandate for public school teachers.

The case concerns an executive order issued by Mayor Bill de Blasio on August 23 mandating that all public school employees get vaccinated by October 1 or be placed on unpaid leave. Four employees filed suit in the US District Court for the Eastern District of New York seeking an injunction to temporarily block enforcement of the mandate, but the court rejected their request. The challengers then appealed to the US Court of Appeals for the Second Circuit, and also asked for a temporary injunction, but the Second Circuit refused to issue one while they consider the case.

The challengers then turned to Sotomayor, who handles emergency appeals from the Second Circuit. They claim that thousands of public school employees will be forced out of work absent intervention from the high court, arguing that the vaccine mandate is a violation of their due process and equal protection rights. However, on Friday afternoon Sotomayor acted alone, without referring the issue to the full court, and turned down their request. This means the city’s vaccine mandate for public school employees has gone into effect.

In August Justice Amy Coney Barrett issued a denial in a case involving a similar vaccine mandate at Indiana University.