Another federal judge blocked the Biden administration’s vaccine requirement for certain medical workers on Tuesday, effectively halting the requirement across the country after it was blocked in 10 states a day before.

The two rulings, made on consecutive days by Trump-appointed judges, amount to yet another blow to the Biden administration’s key initiative to increase workplace safety and coronavirus vaccination rates through such requirements.

The Biden administration issued the vaccine mandate, for health-care workers at facilities that received funding from Medicare and Medicaid, in early November through the Centers for Medicare and Medicaid Services (CMS). It was estimated to apply to some 1.7 million workers at 76,000 facilities across the country, including hospitals and nursing homes.

But in a 32-page ruling issued Monday in St. Louis, U.S. District Judge Matthew T. Schelp, a Trump appointee, said a preliminary injunction to halt the rule was warranted because he believed the arguments by the plaintiffs — 10 mostly Republican-dominated states — that the CMS lacked authority to implement the requirement probably had merit.

He also questioned whether there was enough data about transmissibility and vaccination status, and he said he believed the order was probably “arbitrary and capricious.”

“Congress did not clearly authorize CMS to enact this politically and economically vast, federalism-altering, and boundary-pushing mandate, which Supreme Court precedent requires,” he wrote.

On Tuesday, District Court Judge Terry A. Doughty, a Trump appointee in Louisiana, followed up with his own ruling in a case brought by 14 other states, finding that a nationwide injunction was necessary to protect the “liberty interests of the unvaccinated.”

Doughty cited another court injunction, which halted the Labor Department’s vaccine or testing requirement for private companies of more than 100 employees, at length in the 34-page ruling. He said he believed there was merit to the arguments made by the plaintiffs that the CMS did not have the proper authority to institute such a mandate.

On Jan. 13, the Supreme Court blocked the Biden administration from enforcing a vaccination-or-testing requirement for large employers. Here’s what to know. (Julie Yoon/The Washington Post)

On Monday, the CMS said that it was reviewing the court’s orders and that health-care workers “have a special ethical and professional duty to protect their patients.”

“The vaccine requirement for health care workers addresses the risk of unvaccinated health care staff to patient safety and provides stability and uniformity across the nation’s health care system,” it said in a statement distributed by spokesman Daniel Trucil. “Staff in any health care setting who remain unvaccinated pose both direct and indirect threats to patient safety and population health. That is why it is critical for health care providers to ensure their staff are vaccinated against COVID-19.”

The rulings are the latest setbacks for the Biden administration’s efforts to combat the coronavirus pandemic by increasing vaccination rates through mandates and requirements.

The Labor Department rule, which required vaccinations or regular testing for employees at companies with more than 100 workers, was also stopped in the courts by a panel of three judges, two of whom were appointed by President Donald Trump and the other by President Ronald Reagan.

The rulings in all of the cases are unlikely to be the final word, as the cases work their way through the appeals process.

As cases of the omicron variant of the coronavirus continue to be detected globally, President Biden on Monday emphasized that getting vaccinated is a key defense. “The best protection against this new variant or any of the variants out there, the ones we’ve been dealing with already, is getting fully vaccinated and getting a booster shot,” Biden said in remarks from the Roosevelt Room.