President Joe Biden s administration on Thursday released details about its new vaccination rule for large employers, setting a Jan. 4, 2022, deadline for workers to get their shots.

Workers who choose not to get vaccinated will be required to provide proof of a negative COVID-19 test on a weekly basis.

The rule , which will be enforced by the Occupational Safety and Health Administration, will apply mostly to private employers with 100 or more workers company-wide. The White House estimates that the requirement will cover 84 million workers.

Employers will have to provide paid time off for workers to get their shots.

Jim Frederick, deputy assistant secretary of labor for occupational safety and health, said Thursday that the U.S. had made great progress on vaccinations but still had work to do.

There are still so many workers who are not protected and remain at risk of being seriously ill or dying from COVID-19, he said on a press call.

The new rule technically goes into effect on Friday, but it will be 30 days before certain provisions begin, including a requirement that employers enforce masking in the workplace. After 60 days, workers will have to show their vaccine cards or other documentation, or begin showing testing results.

The rule, known as a temporary emergency standard, has been in the works for months. But OSHA officials said they wanted to give employers more time to prepare, hence the Jan. 4 deadline.