A federal appeals court on Friday reinstated the Biden administration’s coronavirus vaccination policy for large private businesses, reversing an earlier court ruling that had halted one of the White House’s signature efforts to reduce transmission and drive down case counts.

The ruling by the Ohio-based U.S. Court of Appeals for the 6th Circuit was quickly appealed to the U.S. Supreme Court, which is likely to have the final say over the rules set to take effect Jan. 4.

The Justice Department had asked the court to clear the way for the policy designed to protect workers at large private businesses from the virus that has killed more than 800,000 people in the United States.

Under the Labor Department rules, employers with more than 100 workers must require staff to get vaccinated or face weekly testing and mandatory masking. There are exceptions for employees who do not work on-site or with others.

Friday’s 2-1 ruling backs the Biden administration’s authority to issue the emergency workplace directive through the Occupational Safety and Health Administration.