A federal district court in Missouri Monday issued a preliminary injunction halting the Biden administration’s vaccine mandate for health care workers in 10 states.

The Centers for Medicare and Medicaid Services (CMS) issued an interim final rule on November 5 revising the requirements Medicare- and Medicaid-certified providers have to meet in order to continue to participate in the programs. The rule would require staff at those providers to be vaccinated against COVID-19, receiving their first dose by December 6.

A coalition of ten states, led by Missouri and Nebraska, filed suit challenging the mandate. They claimed that it would exacerbate staffing shortages, particularly in rural hospitals and clinics.

Judge Matthew Schelp agreed with the states’ claim, finding that allowing the rule to go into effect would cause irreparable harm to the states and their healthcare industries. He found that “the nature and breadth of the CMS mandate requires clear authorization from Congress—and Congressed [sic] has provided none.” Schelp also noted that CMS acted in an arbitrary and capricious manner by departing from “its long-standing practice of encouraging rather than forcing . . . vaccination.”

Missouri Attorney General Eric Schmitt called the ruling “a victory” and vowed to “keep fighting to push back on this unprecedented federal overreach.” The 10 states where the injunction has effect are Alaska, Arkansas, Iowa, Kansas, Missouri, Nebraska, New Hampshire, North Dakota, South Dakota, and Wyoming.