President Joe Biden announced the vaccine requirement in September, hoping to stem a COVID-19 outbreak and get more people back to work.
The Cincinnati appeals court was chosen at random to hear the challenges to the rule, which requires employers with at least 100 employees to require COVID-19 vaccination or weekly testing in conjunction with face masks at work.
Kentucky, a conservative media company, and religious groups filed their challenges before the court, which has 10 Republican-appointed judges and five appointed by Democratic presidents.
The Occupational Safety and Health Administration (OSHA) issued the rule as an emergency temporary standard, claiming that it will prevent 250,000 hospitalizations. The rule set a compliance deadline of January 4th.
In court, the administration must demonstrate that a "grave danger" necessitated the adoption of an emergency standard, allowing the agency to bypass a years-long rulemaking process.
In its 50-year history, OSHA has issued ten emergency standards, and only one has been successfully challenged in court.
Vaccine mandates are extremely contentious in the United States. Supporters argue that they are assisting in the end of the nearly two-year coronavirus pandemic, while opponents argue that they violate the United States Constitution and limit individual liberty.
A three-judge panel on the United States Fifth Circuit Court of Appeals in New Orleans blocked the rule on Friday, calling it a "one-size-fits-all sledgehammer." more info
The court noted that nearly 80% of working-age Americans are immunized, and many workers, such as truck drivers, are at low risk of exposure.
The Biden administration is expected to request that the 6th Circuit Court of Appeals reconsider that decision. Legal experts predict that the cases will be heard by the United States Supreme Court.