The White House ordered the U.S. private sector Thursday to ensure all their employees are fully vaccinated by Jan. 4, or submit to weekly COVID testing, extending the deadline through the holidays before the mandate take effect.

Business groups had called for the Biden administration to delay the vaccine mandate until after the holiday season due to concerns it could lead to lower worker retention rates amid strained supply chains and a tight labor market.

Under the newly released rules, issued by the Occupational Safety and Health Administration (OSHA), apply to businesses with 100 or more employees, with workers mandated to receive their second shot of either Pfizer (PFE  )-BioNTech's (BNTX  ) or Moderna's (MRNA  ) two-dose mRNA vaccines or a single dose of the Johnson & Johnson (JNJ  ) shot by that date. All unvaccinated employees must start wearing masks indoors by Dec. 5 and provide a negative COVID test on a weekly basis after the January deadline, according to the requirements.

"For our country, the choice is simple: get more people vaccinated, or prolong this pandemic and its impact on our country. The virus will not got away by itself, or because we wish it away: we have to act," President Joe Biden said in a press statement.

"Vaccination is the single best pathway out of this pandemic," Biden added. "While I would have much preferred that requirements not become necessary, too many people remain unvaccinated for us to get out of this pandemic for good."

Under the mandate, companies have until Dec. 5 to offer paid time for employees to get vaccinated and paid sick leave for them to recover from possible side effects. Companies are not required to pay for or provide COVID tests for unvaccinated workers unless otherwise required to by state or local laws or by labor union contracts. Moreover, any employee who tests positive is prohibited for going to work until they test negative.

The new rules do not apply to employees at a workplace where other workers are not present, who work remotely from home, or perform their work exclusively outside. Those who are exempt from the vaccine mandate include those with sincerely held religious beliefs, disabilities, and those with underlying medical conditions that do not allow them to get vaccinated, according to the requirements.

The vaccine mandate, which covers about 84 million workers in the U.S. private sector, is the most expansive use of federal power in response to the coronavirus pandemic since March 2020.